Why does she avoid me if she used to seem to like me?

However, the past few days, I haven't really talked to her that often. This is either because I'm walking with her for a bit and then she stops to talk to her friend but I keep walking or because she runs off before I can approach her for reasons unknown. Today was my last opportunity to ask her out to homecoming but I couldn't ask her out because she hasn't really been talking to me that much within the past few days and i have no idea why.

Occasionally when I do talk to her, she still acts kinda nervous around me. However, I talked to her once after all this and she was no longer shy. She talked to me perfectly fine. Then she went almost immediately back to avoiding me.

Sometimes when I walk by, her friends will all turn their heads to look at me. And though I've never talked to her friends, they all seem to know who I am. I may just be imagining it, but there is this look on their face that tells me they at least know a little bit about me. If they didn't, they wouldn't be giving me the kinds of looks they are. It's too difficult to describe the looks, though. I also occasionally see her looking in my direction during choir. I don't know why this is.

I think she caught me looking at her once and smiled. My choir teacher was moving me around for my position during the concert next Wednesday and she was looking up in my direction. Most other people were just looking forward. My sister had her friend over and I was asking her friend if she did FM gymnastics. My sister replied telling me that, even though her friend doesn't do FM gymnastics, she knows this girl. I told her I'd been considering giving up and she seemed to mock me with "aww."

She seems to have a much easier time talking to other guys and I have no idea what's going on. I am horrified of losing this girl.