Hiya! I'm a Muslim myself. If you do not want to be a Muslim, then it's not up to anyone to say otherwise. It is your life, and no one should interfere. If you are 18 and above, then you should not have a problem facing your parents, and telling them about your belief. If you're under and you're still having trouble, then just wait it out until your 18. If they still disapprove, then say that it's between me and god, not you. They are in no position to impose who is Muslim and who isn't. Although it'd be nice to have you onboard the Islam Train, it's entirely up to you. We certainly wouldn't want to push someone to believe in something he wouldn't want to believe in.
By the way, to all that are mean to the religion of Islam, I pity you. There is no reason to hate on a religion that has been distorted from its true definition over centuries and years. Rather, you should be understandable and know that many are misguided. I'm no sheikh, and I'm not strictly religious, i'm just a bloke who's studying the A levels and minding his own business, but seriously, don't hate on any religion, it's really rude.