What am i suposed to do please help me?

hey im fifteen and about to turn sixteen in a week but not important. what is is that im gay and am out to all my friends and im a leader in my schools gsa but the thing is is that my parents i feel are phobic by the way they look down on people that are way differnt or crack jokes behind thr bak. my attitude at home as been affected by this and its getting to the breaking piont that im to much of a wus to tell them im scared that theyll kick me out or not talk to me etc. please lend me som advice i am so scared