I was in a uni class last semester with a girl who was giving me strong green-lights consistently. Eye-contact, smiling, glances across the room, opportunities for me to start a conversation.

This was consistent for about 9-10 weeks and then in the final 3 weeks in the semester she stopped doing that and kind ignored me. I never spoke to her or responded to her flirting.

During class I was partnered with another girl for a group assignment. The flirty girl gave her a bitchy stare and seemed to dislike me working with another girl as she got defensive when the other girl spoke up in class.

She was very attractive and I was too shy/intimidated. I'm 25 she was 22-23.

Why do you think she stopped?