If you are close to any museums, don't be afraid to try and write or call the people and scientists at that museum. Sometimes they have volunteer programs for young people who are interested in science. It may not always be a paleontology sort of volunteer program, but I would say any chance you get to do a science-type volunteer program at a museum you should consider doing it. Again, I don't know too much about Australia, but you could check this out on the internet, or maybe somebody on this dinosaur list would know. Read as much as you can, and not just about dinosaurs.
Paleontology is a science that mixes in a whole lot of other sciences and activities.
Almost anything you learn in school, read about, or do in your spare time might help you later as a paleontologist. You never know what may or may not help you, so be as open as you can to learning new things. Computers and programming are a good topic to understand as well. Write to scientists whose books or articles you liked or maybe disagreed with. Don't be afraid to write to scientists.