She just broke up with me becuz...?

Ok so my gf just broke up with me cuz we could not hang at her house today because my cuzin had a party that i had to go to. I told her that we could hang out any other day just not today. And its not like i ditch her a lot every other time she wanted to hang out we could. We have been dating 2 months and we are both 16. I like her a lot. And i give her like a gift every week because she is so awesome. She didnt say thank you and neva got me anything. So im just wondering is that a good reason to break up and was she a good gf?