Am I Wrong In This College-High School Thing?

I started dating Jamie when I was a high school senior and she was in 10th grade. Now, I'm in college and there's so many parties and temptation I decided to break up with her before I did anything. She hates me for it and said I never cared enough about her and that's why I'm doing this and not to spare her feelings.

I do care and this is why I did it first. I am honest in saying I will be doing something with a girl here at school and it was gonna happen eventually. She thinks I'm lying. Please tell her I did the right thing in a wrong situation.