Give up on her or keep trying?

Hello, I'm 15 years old and for the past year and a half I've been in love with one of my closest girl friends. It's kind of complicated...okay really complicated. First she started making jokes about being bi with me after a girl in our class came out as bisexual, and I went along with it not wanting her to suspect that I really am. So then she asked if we could "be bi" and she started calling me cute, hot, even sexy. We started "dating", this was meant to be a joke but I think it was much more than that. At one particular sleepover we both attended we held hands all night and she fell asleep in my arms. At another one we spooned, I never wanted to let her go. The only thing keeping us from being in a legitimate relationship was her saying so. The days following our little cuddle sessions I was so happy and I didn't hide it, especially from her.

Then a few weeks later we were texting, and she broke my heart. Another sleepover was coming up and she told me "we can't do what we did last time" I was upset because I loved holding her so close. (At this point I'd like to make it clear that neither of us came out to each other or anyone as bi or lesbian yet, but we had a connection and we both knew it) Her response was "we're just friends, and friends don't do that" those eight little words destroyed me. I was so in love with her and I'd just been told we're just friends. I know she felt something for me too, but I think she was scared. So at the next sleepover, we slept on opposite sides of the couch, which killed me, but we still intertwined our feet as we fell asleep.

We still had a connection, but she was pulling away.She suddenly wouldn't even acknowledge the "fake" relationship we had, may I add that she was the one that started it. Now, over 6 months later, throughout all this time, although she says we're "just friends" she still holds my hands and makes tiny comments to/about me. I feel like she still feels something for me but she's scared of either the fact that she might not be straight or what it'll do to our friendship. I can understand both but I just can't do this anymore, what do I do? Do I try harder, or do I give up on the girl I've loved for the past year and half? I really don't want to give up, because I know what we had is still there, she still does little things that convince me, but it's not the same as it was before. Do I wait for her to come around, or do I try to get over her?