Why won't she just admit that she's bisexual too?

Last week I went to a friend's house to do our homework and we ended up making out on her bed after a while (don't worry, we finished the homework first). We had already kissed a couple of times before, so it wasn't something out of nowhere. I'm pretty sure she was very much into it, I was too.

Yesterday we were talking to our friends about boys, love, etc. Everyone knows I'm bisexual, when the conversation moved towards 'are you attracted to other girls?' I was pretty sure she'd admit that she was bisexual too, instead she said she's "100% straight".

Why would she lie like that? I don't think it's because of her parents, they're really nice. Very liberal and not religious either. It can't be fear of discrimination, our country doesn't really have that. It's not a big deal but I just wish she'd be more honest about her sexuality.
Why won't she just admit that she's bisexual too?
Add Opinion