I have liability only on my cruiser, and full coverage on the SS>
I say depends where you keep the bike, and what you use the bike for. if the bike is being parked in the open (incl. Condo parking lot), and in Toronto, then i'd recommend you get theft protection.
because of your age, i understand you don't have much of a choice. if you try full coverage it's the insurance company's party. i would say just try to best deal possible. take your chances and stick to liability only. BUt you have to more careful where you park the bike, especially if downtown. also, look into getting a disc lock.