your parents love you and think that they know what is best for you. they may or may not. so understand that as hurtful as what your parents say, it is with the best of intentions. now, we all know how useful intentions are. so bear that in mind.
since you're almost out of high school, i'd recommend that you sit on it with your parents and try to go to college away from home.
it's not possible to
learn to like anyone. it is possible that you might meet a girl that you do like, though. i'm not recommending that you deny what you may be, but i'm personally bothered by people who lock themselves into a box. i don't advise a great deal of "experiementing" in school, but do meet lots of people and learn new things. but i'm not really the best person to ask about this. talk to people who are sympathetic. tallk to people who have been through this. but as someone else said, try to avoid people who would push you in either direction.
take the time to figure yourself out. you might be surprised at who you meet. if you learn that this is in fact who you are, your parents will either get used to it, or they won't. it doesn't change your value as a person. and i don't know what you believe, but who they think god is doesn't change who he really is.
you haven't failed your parents. you haven't failed yourself.
but for god sakes, whatever you do, be smart and be safe. disease is a big danger. but it's a danger no matter who you decide you like.