Well hello, I am new here as you can see. I am an Australian male who just turned 18 a few days ago and booked my first flight to Malaysia to take off on a backpacking journey solo. It will be the first time in Asia and my first time overseas alone and it is a little daunting now my flights are booked. First off I will be heading to Malaysia then onto Thailand, Laos, Vietnam and Cambodia. I plan on being there for 3 and a half months on about $7000-$8000 AUD, Do you guys think that is a achievable budget? Also my main advice here is that I have never traveled alone before, it has been my dream to do this and am finally doing it but am I too young? I just finished high school and it feels so surreal, is there many travelers my age backpacking? Anyways I am super excited and will take on any advice I can get from you guys so please let me know as much as possible. Also I will be leaving on September 12th this year and plan on staying until around December 20th so if anyone is in SEA at this time, I am looking for a travel buddy :)

The budget is enough. There is nothing at all to worry about. This trip may feel very surreal and unique to you, but the journey you are about to embark on is a very typical SE Asia backpacking jaunt that thousands and thousands at your age do every year. Make sure you have your passport, visas if needed, bank card, health insurance, vaccinations if needed, guidebook if that's how you travel and then just stop worrying and go. You will meet people and have the time of your life.
Spend some time scrolling through the Thorn Tree and reading threads that are of interest to you. You will find all kinds of info. You'll probably find lots of threads quite similar to your own whether about 'am I old enough' or 'do I have enough money'. There is nothing new as max says in what you have written.
Look for threads on what to take (which pack, what to put in it).
Look for threads on how to handle your money. (best bank cards to use)
Look for threads what things cost.
Look for threads on what to watch out for. (have street smarts)
READ, READ, READ.
You have until September so there is plenty of time to prepare.

Hi Mamastra,
Off course setting off on your own for the 1st time is somewhat daunting but I can pretty much guarantee you within a week you will be having the time of your life & wondering what all the worry was about. You will soon hook up with other young travelers in the resorts or cities you stop in or on the buses or trains you travel on. You will soon find some people to travel part of the way with, go your separate ways, make new friend & then keep bumping into old traveling companions.
One easy way to meet fellow travelers & often make friends for life is to do an organized activity. Diving course, cookery classes, massage course or the like. I find on an organized trek over 2 or 3 nights I usually make good friends, often keeping in touch for years afterwards'.
Your budget is extremely healthy & I expect you will be able to return with a fair portion of it unspent unless you go really wild or spend all your time on the more expensive Southern Thai islands.
I'm sure you will have a fantastic experience & return home impatient to save for your next trip.

Thank you so much guys! Reading these comments for some reason has shot my worries and am now just ready to get this planning started. I really appreciate it.
Have three photocopies of all your travel documents - your passport, flights, accommodations if booked, travel insurance, credit cards, bank cards, student card (if any) etc. Give one set to someone at home, have an online copy and take the other two with you but keep them in separate places. Keep your passport either in your hotel safe or on your person.
Never leave money, passport or valuables in your room or in you pack even if it does have good locks.
You will need HepA/HepB vaccine which is Twinrix. The first dose is given 6 weeks before departure, the second two weeks before. The third is given 6 months after the first. This will give you protection for 10 years (approx). If you only have the first two, then if you travel again, you will need to go through the whole process. These are private prescriptions, and cost around $70+ each. It is a good idea to speak to the pharmacist to make sure he has it in stock.

I find I can travel fairly comfortably in all of these countries on about $60 per day for everything (accomm, food, transport, spending money, entry fees etc). So in your case 3.5 months is about 100 days = $6000, so you're about right.
But you always spend a little bit more than you budgeted for, you never spend less!! You will find lots of activities that you want to do like snorkelling, boat trips, rafting, trekking, cycling tours etc etc. and all these add a little bit to the daily budget. But if you're sensible with your spending you'll be fine.
You will work out pretty quickly what kind of accommodation you prefer. The cheapest is shared dormitory rooms (sharing with 3-4 others) and a shared bathroom for often $5-10 per night. But in many places you can find decent private rooms with a private bathroom and air-con for $15-20.
I would recommend finding a specialist travel doctor in your home city and going to see them about 6-8 weeks before you leave.
They will advise you on which vaccinations you really need and don't need for the areas you are going to. They will also talk to you about malaria tablets etc. Personally I suffer from motion sickness and sea sickness and you can get tablets for that if required.
I would suggest buying a Lonely Planet guidebook and start reading it well in advance. They contain masses of info on places you can go, things to do, transport, accomm. etc etc.
There is a recent one called 'Northern Thailand. Laos, Vietnam and Cambodia' - although it doesn't cover southern Thailand and Malaysia.
'South East Asia on a Shoestring' is the bible, but it covers all the countries in a lot less detail and is a big heavy cumbersome thing to carry around.
Just read lots and ask lots of questions. Keep coming back to this thread and I'm sure people will be happy to help you.
Buyers Remorse the day after you book a big ticket...is normal... Just go with it...
I often just forget about the trip for a few weeks after booking a ticket...just ignore it...block it out totally for a while...
Slowly, you'll come around to the reality the trip is really booked...and you have to go... Only then start serious planning ...
As the departure date nears...you will have accepted your fate...and can start packing and planning...
Generally having your hotel/hostel booked in advance for your first destination...will cut the anxiety level down... Because at least you'll have a room ready... after your flight...and can settle in for a while...
Work on possible lodgings for your second and third destinations...if possible...but don't book things too far in advance because on a trip things can change...and you don't want to be boxed in...too far in advance...
You destinations are all cheap and very interesting...and they are used to tourists... Don't avoid "tourist traps" for your first few weeks ... until you get your "road head" and get a feel for the local culture...
In other words stay on the beaten track for a while...at least there they will speak English...!
Study up on Buddhism now...so you'll understand what you are looking at in South Asia... Read up on these countries from now until your leave... But don't take many books with you...maybe just your well thumbed LP... Books are heavy and there are plenty available on the road...
Solo travel can be very good for the self directed person...because group travel is only as strong as its weakest or stupidest link... And you'll likely meet similar fellow travelers on the road...at bars, markets or on tours...
Tour buses will get you to the various places you want to see at your destinations... I prefer smaller buses where you get to know the other people... Book these through your hostel or from established companies...not some guy with a card table on the curb...
Finally since you are from Australia...you are not really that far from home in any event... So give yourself "permission" to abort the trip and fly home if you want to...Its OK...
But very likely you'll be used to the road quickly... Things will work out just fine...
I'm very jealous you're about to do SE Asia. I did five months in vietnam, cambodia, laos, thailand and malaysia last year and spent about £5000. That was drinking every day, doing plenty of trips and tours and basically not skimping on anything so your budget is easily enough. And I had the best time of my life!
As a single 18 year old lad I'd rush through malaysia as its a bit dull and you only have 3 or so months. Pulau Tioman was good, (proper chillout paradise island), malaka is nice but dull and kuala lumpur was just a big city with no night life. I heard the Perhentian Islands are also good but we didnt make it there. We picked Langkawi instead which was a bit crap to be honest.
All the other countries on your list were amazing! Spend a good 3 or 4 weeks in vietnam and do it properly from top to bottom. Most asian country of the lot with not too much western influence and plenty of culture and nightlife. Cambodia and laos can be done in 2 weeks each really. Thailand again, spend a good while there. Do north and south as theres plenty to see other than the islands.
Hope you enjoy it as much as I did! And don't worry about being solo or 18, thousands of you in the same boat out there waiting to meet friends so you won't be alone for long.