well if it's like that, it could be a traumatization type thing, or else this will be one of the things she just feels touchy about, either way you'll have to deal with it. Maybe just waiting alone will solve the problem, maybe eventually you could talk to her into seeing and speaking with someone else who could help her problem, either way, don't be consumed by it, after all you are young and have much more time to grow together (hehe, 'grow') or even though it may sound negetive, alone for that matter.

ie, let her decide for herself when the time comes!