I'm Bisexual but I'm afraid to tell my friends because they'll judge me. What should I do ?

Soo, I'm bi and I want to tell my friends but I'm afraid they'll judge me because they all make fun of Bi's and lesbians. I don't know what to do. Last night I told my friend and she was like you're kidding right and I had to say yes because I didn't want to loose my bestfriend. What should I do !!