Study the DiCarlo escalation ladder and use it on her.
Just kiss her when you feel like it.
Girls just wait for guys to kiss them and they think you're stupid if you don't.
All that stuff she said about age and boyfriend is bullshit.
She was just testing you to see if she could shake your confidence.
If you let it bother you, then you lose.
Don't believe what she says. Watch what she does instead.
Next time she says some dumb shit like that, treat it like a joke and make fun of her.
You could tease her and say she's not pretty enough because she's too old.

muhahahahaha
That will fuck her up and make her desperate to prove you wrong.
Study everything by SwinggCat and Vin DiCarlo.
She's just one girl. College is one of the best places to meet girls.
You don't need her.
There's probably a lot of other girls in college that you'd like more than her.