<human>: A bit of background: 
As the age difference between us shows, she did go to college before I did and she did have a boyfriend in that time. My girlfriend has been open to me about her previous relationship, and so she has told me that she had sex with her ex-boyfriend.

However, when it comes between us, we practice none of it. Not after what happened a few months back. This was my first time. In the moment of heat, we were going at it, but I stopped. Stopped as I wasn't wearing any protection and she wasn't on birth control. She, initially didn't seem worried at first, but, after seeing my puzzled look, told me that her ex used the pull out method all 4 years they were together and during those 4 years, she was not on birth control. The next day was a bit awkward. I wasn't sure what to think. Wasn't sure how to process what she told me. For her sake, I told her I was fine. She herself seemed worried about me and I didn't want to make the night anymore awkward. 

So even though it's been a few months, I'm still thinking of that night. Still thinking of how to process the events of that night. Thinking of how come her ex got to be that intimate with her and yet with me not so much. When I bring it up, she just tells me that she doesn't want to risk pregnancy and that she has school to finish. Plus, I have the feeling she doesn't want to talk about it. Of course I don't want to jeopardize her future, yet, wasn't she and her ex in the same position? Both were students, but yet did it anyway. I'm not sure how to feel about it. Yes, we go out and enjoy one another's company…yet this thought lingers in the back of my head. Maybe I'm just being immature or maybe it hurts because my first time with her didn't go so well. I just want to get over this and I guess maybe writing it here will help, but I don't know anymore

Can you summarize the given text in a few sentences?
<bot>: Girlfriend had sex with her ex-boyfriend before she met me. However, we don't share that degree of intimacy.