Forced herself to become a bi?

I'm bisexual and a friend of mine is trying to "force" herself to become a lesbian or bisexual. Is it just me or am I the only one that feels offended? I thought she was joking around at first but I can see she is desperate. I heard of gays/bi/lesbians/transvestites that try to erase their homosexuality but that usually ends up into suicide or something harmful. I'm worried about her but I got no idea what to say to her. Help!