Welcome to the path of inner peace and happiness. You are a very special person to be interested in Buddhism despite your young age. You are also very lucky to have parents who will give you the freedom of choice come 18 years old. You should respect your parents' feelings and advice. That doesn't mean that you cannot practise Buddhism now. As you know the Buddha's teachings are very practical. Just follow his teachings to be good, avoid evil and be always mindful of these two values; you will be in the right path. I am sure your parents will agree with these universal principles. As far as your mind is concerned you are a Buddhist. No one can take away your mental decision. When you turn 18 you are free to declare to the world that you are now "officially" a Buddhist, and with the "blessings" of your parents. Who knows, your parents may be impressed by your Buddhist virtues that they may want to know what is it in Buddhism that their intelligent son can be so devoted to.
Best wishes to you.