Most Helpful Guy
You did nothing wrong. Don't try to get an explanation for anything she would or could say would ultimately be irrelevant and inconsequential. You had two years with a chick you liked, be grateful for that.
" I just wanna know how I can get over her she's the best girlfriend I've ever had? " -
Time, keep yourself busy, and eventually start trying to see other girls.
"Best girlfriend I've ever had," are you kidding me with that? That's ridiculous, you're way too young to make such a statement. Unless you've had many relationships in your past, I'd say that uttering those words was a lil' premature. Fear not my friend, there will be plenty more to come.