Now I'm studying in the preparatory course and want to study medicine at the University of Sydney. Can I study medicine as an undergraduate? If so ...
There is medicine. Didn't you decide what to major in when you were preparing for school? You're great. You should decide what you want to study before you go to preparatory school. When you finish the preparatory course, you may be able to take the exam, but you may need a quiz or something. There should be no admission requirements, as long as the IELTS score is enough.