I don't know much about Oz, but if your folks are OK with it, you could probably start lessons right now. Probably can't solo until you're 16 at least (don't know the Australian rules), but if you can scrape some money together, you could start taking those first steps (maybe Mum &Dad could give you a coupla years' worth of Xmas and B'day presents in advance in the form of cash?;) ) . Most flight schools offer a slight discount for an "intro flight"- a real lesson that you can put in your logbook. Who knows? There might be a school that will let you do some work for them (cleaning planes, sweeping the hangar, etc) in exchange for time. I had to wait about 2 years after my first intro flight b/4 I started taking lessons (in my mid-30s), and at one point I was cleaning planes and doing carpentry work for the FBO in exchange for time.
If you want an airline career, an "ab initio" program would of course be a good idea; they like to hire people who've been learning things "the company way" from the beginning.
So start hunting- obviously you have the Internet at your disposal... fire up that search engine and good luck!!
