Whats wrong with being bi? gay? lesbain? or transgender?

i am a girl. my cover name is haysus..i need one because my parents can not find out that i am bi. i am 17 and about to graduate from high skool.i have to hide my bisexuality from my parents because they are strongly against it. i have a girlfriend, wev been dating for 7 months.she is my 3rd serious relationship. she comes over my house not frequnetly, my parents have a strong dislike for her, and they dont even know her. i am tomboyish, and my parents are really upset about that, often blameing themselves for letting my play with cars and power rangers as a child. iv been beaten for being who i am, for being tombyish, always talking to other girls and not having any interest for guys. iv almost been caught several times and have been beaten cuz of their suspicion. i constantly have to delete my txts and emails, i have to be super carefull n facebook, and i have to hide. since i was 13 i would pretend to be their perfect little daughter at home and since i was 8 i would bring in clothes secretly and change back into myself at skool. things havent gotten any better.infact thery getting worse. my parents said that if im bi or lesbain, they wouldnt be affaird to go to jail for beating the sh!t outta me. n that i wont be a part of our family any more. i would be disowned and kicked out with nothing.n no one from the family will take me in, n ill go to hell. my parents and i are catholic. i belive in god i truley do, is it a sin to be this way? i thought god would forgive you if you have be a good person, i have done nuthing bad..im not a bad person so why do they say this? i have a few more months till my 18th birthday.. n hopefully i can get a good enough job to afford an appartment somehwere while i go to college. i dont want to lose my family (suprizing but true), but i dont want to keep hiding having to pretend to love a guy that i dont. i just want them to love me for who i am...but theyll never understand..