Just to add my own experience and reinforce what others have said here, get along to the local cadet Squadron and start there. I did the Air Cadets in Canada as a teen, 12-19 years of age, and I still have friends from those days, going on 30 years later. It is a fantastic organization, especially so for a youngster interested in flying. I eventually did my glider license and PPL on a scholarship, which of course is a huge first step for anyone, financially and for getting that experience. I'm not sure if that is available in Aussie, but nevertheless, the chance to be around aviation, involved in one facet or another, is great motivation and an excellent way to learn the industry, and at the very least, make a group of good friends.
I can't recommend it highly enough.
Nosey