Strict Grandmother?!?

Ok i'm 14 and my grandmother is 70. Both of my parents is dead. My oldest brothers rebeled against her, and hate her till this day. She is a STRICT CHRISTIAN I cant go any where unless a nother christian who is best friends with her is present and dem people are like 80 and they all are a bunch of fakes seriously! I cant even take a walk around the block by myself. I stay in the house 24/7 like i'm in jail. BUT even worst I GET HOME SCHOOLED! everything I do I have to do behind her back...I cant have a bf shoot I cant even talk to a guy. wat i'm pose 2 b gay? is dat wat she wants? she trys 2 pick my friends, i'm not aloud to go to ANYONES house. I want to go shopping at the malls, hangout with friends like a normal teen. I dont wanna just go to church. because thats the only place she aproves of. i have not done anything to loose trust, I cook, clean, I take care of her, i'm a good person & I need to make my own mistakes and grow up.my problem is i dont kno how 2 tell her this. Help!