Thoughts On this Story?

This is something that happened to me with a girl a few years ago so its in the past now but I would like to hear back from others to see if they have some sort of logical explanation besides the obvious rejection explanation since this is the only time I have personally experienced something quite like this.

There was a summer class that I joined at that time that was going to last 5 weeks and we would meet up once a week. On the first day we did introductions and during one of our breaks a girl approached me and asked me a question regarding something I had mentioned in my introduction. Through this exchange we became friendly and would talk to each other during our breaks. As the weeks progressed she even initiated a hug and even gave me a kiss on the cheek when we said goodbye to each other.

In my mind I could not see more obvious indications that she was into me and I had a shot with her. On the last day of class I decided to ask out for lunch for that coming weekend and she said yes. We exchanged numbers and said goodbye. In the days leading up to our date we starting texting each other talking about school and where our date would be but then eventually I stopped hearing back from her.

I sent her a text back after I didn't hearing back from her thinking maybe we would talk about something else in the event that topic had ran its course. However I still didn't hear back from her, I looked back at our last exchange to see if maybe I had said something off putting or rude but I never once felt like there was any of that taking place.

Needless to say I was very confused about what had happened because initially this girl came to me not the other way around. Not only did she lead me on and accepted my invitation to go out but we also texted each other after the fact. I would understand why she would say yes to be polite and then never respond back since that was the last day of class but to actually continue to talk about our plans and whatnot afterwards almost seems like too much effort assuming that was her intention.

So my question is what do guys think probably happened? Is it common for girls to do this type of thing?