Girls, What causes a girl to glance at a guy when walking past him?

This girl I really like glanced at me a few times. One instance was I walked pasted her and I saw her eyes move towards me. Another was she walked past me and I was talking to someone and i saw her look at me.

I did start talking to her too and I noticed the moment I did, suddenly she was ensuring I got a harness too for the training course we were about to start.

Updates
1 y
She is acting quieter with me compared to other people in the same social setting as me. It just seems like she kinda avoids me, however she will come over and start small talk with me
Girls, What causes a girl to glance at a guy when walking past him?
Post Opinion