Not interested, but she’s interested?

TLDR: asked a girl out via note, she never got back with me, but 3 months later it seems like she’s interested

Long story short, I (15m) had my seat in class next to a (15f) girl for 3 months, we talked some and had some connection. After the teacher randomized the seats in class, we stopped talking. Maybe a week after the teacher randomized seats I placed a note on her desk as I was walking by, and haven’t heard from her since. The note basically said that I enjoyed talking with her, and I wanted to go out with her, along with my phone number. It’s been about 3 months since I placed the note on her desk. Normally I’d leave it there, and that was the plan. But a few days ago, it was as if something had changed and it seems the script has flipped a little bit. Of course the world doesn’t revolve around me, but multiple times during class I’ll see her glance in my direction, and just a few days ago she did this weird thing where she looked in my direction for a second, looked away, looked back for a second, looked away, looked back AGAIN, held her gaze, and stopped looking the second I turned my head to meet her gaze. I’m not sure what is so interesting behind me, so I’m gonna (assume) that she was looking at me. Just today I counted multiple times she did quick side-eye glances in my direction. This is starting to become a regular occurrence every day. I was talking in a group that was looking at an old yearbook because what else is there to do, and her friends found a picture of her and called her over, and way after we moved on from the topic of her picture, she stayed standing around (maybe 2 ft away from me), directly across from me. But she was never speaking, just listening. She knows everyone in the group, so I don’t think it was because was shy. After a while of maybe only saying a couple things (one of them was just saying “now we lost the page” to a kid who messed with the book). But what do I know, that’s why I am asking for advice.

Whether she’s changed her mind, was too shy to text, or just flat out doesn’t like me is up for debate. These signs are ambiguous, and I would really appreciate some outside perspective. I would like to ask her face to face, but it’s been so long that I want to be sure that she has some interest before I ask her lol.