<human>: title is a pretty solid summary. 

I was in a short relationship before college that got serious way too fast. about 3 months in, we were fooling around and things were heating up to a new degree when she suggested we have sex, adding "I have condoms here." I, being a horny 18 year old idiot agreed, even though I had been holding out to this point for a solid, committed relationship. We did it once, it was awful, and shortly afterward I left for college and the whole thing fell apart. I am now determined to not let stupidity get the better of me again, and am once again waiting for that solid relationship before having sex.

Cut to now. I've been with an amazing girl for a little over a year now. She's smart, funny, capable, and beautiful. We've had arguments, large and small, but so far we've worked everything out and for the last 5 months things have been great, Except for the aforementioned issue. She's fooled around and given and received oral, but she's waiting for a stable, committed relationship, as I am, for sex.

So for everything leading up that, we've been great together, both publicly and privately, and lately, sex is beginning to come up a lot in private conversation. We were both clear up front about our intentions in that respect, and she knows my very limited history. I feel good enough about this relationship that I'm ready when she is, and I have good reason to believe she's nearly ready herself. 

During a conversation today, things turned back to that topic, and after some hesitation, she informed me that every time she thinks about sex with me, it starts out good thoughts, but then turns to thinking that it wouldn't be as good as it was with the first girl, even though she knows everything I described in the first blurb here.

So my question then is this: is there any way I can reassure her that this wouldn't be the case, and that my previous experience won't affect our relationship if we have sex?

Sorry for the length, but I wasn't sure how to make the situation clear with less text.

Can you summarize the given text in a few sentences?
<bot>: I've had sex before, girlfriend of one year hasn't. She's worried it'll be worse with her and damage our relationship.