Just my 2cents here-- talk to a neutral person, professionally who has some awareness of the issues of bisexuality. Your friend stating she is homophobic is a just a reaction to another person's declaration of embracing their sexuality. It might be this is scary to your friend and depending on her own personal growth and ideas, this might have been a way to distance herself from the uncomfortable feelings she has regarding her own sexuality.

Maybe it is because I am older (59this year) but the whole process of determining your own personal preferences sexually is constantly evolving, at every phase in your human development. So where you are in one decade may not be where you are in the next.

If it was me, I'd share with my friend how much I value my friendship with her, and also let her know I have had my own questions and discoveries in my evolving sexuality. I wouldn't want to scare her off or make her uncomfortable; but I also wouldn't deny who I am, or that I am open to giving and receiving love in ways that might appear to fall outside the "norm" (whatever the hell that is).