Something like this happened to me, too

Just the other day.

I stopped in a small cafe with my significant other. There was a girl who was probably 10 sitting at the far end of the room staring at some papers that she was writing on (summer homework or something, probably) and she looked bored. She had straight dark brown hair a little past her chin, straight bangs and glasses. She was pretty cute. I sat at a table furthest from where she was, which was still pretty close cause the place was small. I was facing her and as I stared out the window I would see her glance over at me and stare for a while. Our eyes met a few times, too. Her dad's phone rang so he stepped outside to answer it. She then flipped over her paper and started drawing. She would look over at me and then exaggerate certain motions as if wanting to be watched. She would flip her hair a lot and when she used the eraser on her pencil, she would really lean into blowing the resulting dust away, and always staring back at me. Such a change in behavior from the bored looking girl I saw when I walked in.

Like you said, I don't think I'm all that bad looking and I don't exactly attract attention either, but it's good to know that young girls aren't really shy about liking guys a decent amount older than they are.