Hi man,
Good advice in this thread, screenshot it and write a list out afterwards of the good ideas and try them out.
There is a documentary made by another aussie who felt like you, called "Fat, Sick and Rready to die" - it is about how he solved his weight loss, and him wanting to help others - so he travels to America to talk to fat people there.
His regime is to blend all his food, and eat a varied selection of organic vegetables, and walk every day.
Walking is an awesome exercise, it also puts you outside and for me it clears my mind and i feel a lot better after a while.
Swimming is good too and nice for variety, also takes the stress off your joints and is relaxing.
Start a good habit of that. Drink plenty of water, eat veggies, dark green are the best, but a variety is the way to go.
Then lean organic meat, chicken is good.
Minimal carbohydrates, and a little bit of healthy fats each day, cheese, olive oil, egg - but just a little to keep things balanced.
Avoid anything with sugar or any kind of junk food.
It is easier to stop one thing at a time, and change it for something good for you.
Your taste buds will adapt to the new foods after a few weeks of eating it every day. You'll begin to like it.
To build your confidence, join a social club without pressure or stress. Like a book club once a week as someone else said.
Study something new and work hard at it.
Aside from that, find a job and start saving money. If you spend the money, invest it in yourself, in training or the good healthy food.
Find ways to challenge yourself.
For exercise, don't strain yourself, stick to about 85% of your maximum and build it up bit by bit.
Be positive, you are young and have the right attitude, make it happen.