Just make sure you don't go overboard with work. We don't want you going to bed and waking up with slit wrists (and it has happened).
Uni is fun for the first semester. As much as I hate it, my first semester was nice. I met interesting people, some who are close friends now, others who I want to stab in the face. Depending on how well your first semester goes (in the sense of meeting people) you will decide then whether or not you like uni or hate it. Once you hate something it's hard to stop, so try and think positively.
Medical Science eh? I believe UWS is opening a medical school soon, if not already, will you be one of the first to get a graduate MBBS, or are patients not your thing? Whatever you want to do, good luck with it.