Relationship trouble! help?!!?

I've been dating a girl for a little over 2 years now. we're both 18 and heading to college next year. I'm in love with her. we get along great, we love hanging out, but we arent that clingy high school couple bc were both busy with sports and stuff. but when it comes to the physical part, shes always wanted to move very slowly. for that last year its gradually become a bigger and bigger issue for me, and its culminated in some recent arguments. she says shes uncomfortable moving any further (i guess lingo wise wed be on 2nd base) and she doesnt kno why. i really dont want to pressure her, but how do i reconcile what i want with her comfort? is she being weird? am i? should i just suck it up and forget about it? im so frustrated and confused