My girlfriend afraid to have an , what should I do?

My girlfriend and I have been going out for 9 and half months, and I would never have guessed she was a virgin. She is such a beautiful girl on the inside and out, I mean she's gorgeous!!!!! And can have any guy she wants. She is 24 years old and wants to have ; but every time we get close to having she freaks out! The last time I went down on her for the first time everything was going fine then her legs began to tremble; until she was on the brink of an , and sobbing, no, over, and over again. I immediately stopped and held her in my arms (like always when she about to have an !) I held her in my arms while she cried, and told her everything’s going to be okay. I've tried several times to get her to have an , but nothing works. She’s too afraid! I thought that maybe she was d or something like that but she ured me that’s not the case, and that she’s never had an before, and gets a little frighten when she about to have one. I want her to be ready before we have for the first time but I a man and I need to get laid!!!! Don’t get me wrong I love her very much, and care about how she feels, but how can I help her over come her fear?