Most Helpful Girl
Before making any drastic decision, I think you should talk to her. Communication is the key. We can throw you a bunch of maybes but in the end, we don't know the real reason. Maybe she'd like to keep her options open like what the rest said on here, maybe she's a commitmentphobic, maybe she just doesn't want to move too fast and likes things going a snail's pace. You should be honest and tell her how it makes you feel. How do you expect her to be vulnerable when you won't take that risk either.