It's hard to tell. You did not really provide enough detail. Maybe you did not make a move fast enough. Maybe you just weren't her type. Maybe she was bored. There are a ton of reasons that she ended it with you. I've read online about a girl breaking up with her boyfriend, because she didn't like the way he smelled after he played basketball.
The reason could have nothing to do with you. You just got to keep going out there and meeting other women, who will be interested in meeting you!