What protein should i buy?

Then go with whey protein does not really matter which ones. Make sure you take 2/3 of a scoop since you are under age. Some good whey proteins are body fortress, six star. IF you live in the states go with nitrous oxide supplements it is like steroids buy no illegal and good for you ( do not overdose on proteins or NO it can harm you and possibly kill you. Happened to some body builder) GOOD LUCK!