Bisexuality Support Group
Bisexuality is a sexual orientation which refers to the aesthetic, romantic, and/or sexual attraction of individuals to other individuals of both their own and the opposite gender or sex. Most bisexuals are not equally attracted to men and women, and may even shift between states of finding either sex exclusively attractive over the course of time.
tell them you may not have been with a girl but you have feelings for both men and women
im a bi male but ive only been with girls but I know that I like men and actually prefer them to women
just explain that you know yourself more than they can and that if they cant accept you for you they aren't worth being your friend