I started talking to a girl this semester in my class. I'm inexperienced with game, and she has a boyfriend, so I did not try to pick her up, even though she was decent looking. We started talking during groupwork, and she began to sit in the desk beside mine after a while when we were not doing groupwork (I used to sit by myself). One day, she asked if she could put her number in my phone, and I obliged of course. This gave me the idea that I might have a chance with her.

Shortly after this, she began to take interest in hanging out with me. I talked about how I wanted to go to a school play, and she also said she really wanted to go, so I said I'd see her there. She asked me every day if I was still going, and I said yes. Day of the play, hours before, she flopped on the plans, making some excuse about having to go out with her family. I told her we'd hang out some other time, and she said to go see a movie. I told her we'd go friday, and she at first agreed, but flopped on that too.

I drove her home when she was hanging out with me and another friend skipping school, and she asked if I wanted to go to an amusement park after our exam tomorrow. I obliged, and she texted today to confirm we were going. Just now, she backed out again.

It is really confusing me about how she is inviting me out, and then backing out at the last minute every time. I am not fixated on this relationship, there are always other girls. But I am wondering why she would invite me out and then constantly back out. Advice would be appreciated, and if additional info is needed, I would be glad to supply it.