what sort of music? if you like classical, then you will have to study music 2 for your hsc, or do ameb theory up to and including grade 5. if you like musical theatre/pop music/commercial music, you don't need to go to university- take singing lessons and get yourself noticed through youtube, busking etc. if you like EDM (yay!!)- theres a good course at UTS called sound and music design, or a bachelor of audio engineering and sound production at JMC, and also DJ Warehouse training which isn't a university.