Consider doing Physics as well as Chemistry. I'm not sure about the VCE but the nsw HSC Physics and Chem courses are pretty good, I know that Chemistry has given me a much better understanding of a lot of stuff relating to fuels which has helped in my lessons. There isn't much in the way of aerodynamics in Physics but I suppose it helps you understand things like lift with all the quantum physics we do. As for uni if you want to get a CPL out of it you will find it is rather pricey, UNSW charges close to 100000 for their Aviation (Flying) stream and you get no assistance for it too!
EDIT: Just read you aren't looking for a CPL. Not sure how it works at RMIT and such but I know at UNSW you can choose a broad selection of subjects in 1st year science without locking yourself into a major. They also have a thing called gen ed in which you have t do electives not explicitly related to your major, I like the sound of that course because I can major in Anatomy and Pathology which sets me up for postgrad med, and I can also do some aviation or aeronautical engineering units just for interests sake.