My advice would be to follow the advice of Pinefamily. In addition to the books they have suggested don't just go for books on keeping reptiles also try and broaden your knowledge & get your hands on Rick Shine's "Australian Snakes, A Natural History", "Pythons of Australia, A Natural History" by Geordie Torr, any field guides on Australian snakes such as those published by Steve Wilson & Gerry Swan. Anything by Chris Mattison.
Asking for things like this for birthday presents etc will show your parents that you have a genuine interest in reptiles.
As well as he above if your old enough consider what Mike (Bluetongue1) has suggested and ask to be allowed to volunteer at a wildlife park. Either way ask to join a herp society and get your parents to attend meetings with you. It's an excellent way to let your parents see the people involved in world of reptiles first hand and break down any barriers. Even if you can't attend meetings regularly, as a member you'd be eligible to go on field trips and receive newsletters and periodicals.
I was lucky as a kid to have parents that supported anything that interested me and I've continued along the same lines with my kids. Seems the effort was well worth while.
The little girl in this photo is my daughter at 3 years old when my wife and I owned and operated a live reptile display. She's now 21 and has a menagerie of her own which includes birds, rats, mice, dog, pythons, beardeds, bluetongues, knob tailed geckos & frogs.
My son at 7 years old with his Olive Python (that is now touching 4 metres).
Both the kids with the Olive
My boy last year at 15 helping to relocate a couple of Red Bellied Blacks and a large carpet. He's got a couple of his own snakes these days but loves to come out with me when we do night spotting around here and assists with cleaning enclosures which includes vens. Also used to come with me to remove troublesome Browns in Inverell since 10 years old.