You know I find these type of comments funny.
I too have been in this type of relationship and I've been in the other type, where sex is the name of the game. And I can tell you the difference very specificially. With one, we both didn't any big thrill out of it, and the other, we both had a blast so if she enjoys herself and has fun, she'll not only going to keep on doing it, she'll even initiate it.
To me she's basically telling you she hasn't had a great history in the sex department and so her expectations are low. Work with it, and if you can get her off the first or second time you're intimate you're home free.
Think about it what's the worst that can happen? (outside of her getting pregnant..lol)
I have friends who marry girls like this. Where they rarely ever have sex unless they are trying to have a kid. I dont wanna spend hours on end going shopping,dinner,tv,walks etc and only get sex 1-2 times a month.