What to do in Malaysia?

I know its a while of but in around 18 months (not this christmas, but the one after) i might be visiting Malysia. It is quite a small chance as it will be because my sister might move there for a year with university but there are only 42 out of around 150 places. I will be 15 at the time but what is there to do? We will be staying in kuala lumpar the whole time what kind of stuff is there for teenagers?waterparks, themeparks, beaches etc.? Or is it all cultural? Also what injections will i need? (from uk)