My girlfriend wants to stop having ...?

Heres the deal. My girlfriend wants to stop having until she gets married. She has apparently rediscovered her Catholicism. Anyway, I am fine with that because I actually do want to marry her. The only thing is, she isn't planning on getting married for a LONG time. She wants to go to grad school and be well established in her career. I don't know what to do... I love her and want to stay with her, but I'm 20 years old and don't want to give up having while I'm in my prime. I just can't imagine being celibate from 20-30. What should I do?