Does she have a counselor or survivor's support group?
If not, I'd suggest you help her get one or both.
Then I suggest you talk with her: it might help to make clear that your reticience is NOT about thinking she's spoiled or sullied in any way. It's about concern for her because often, rape survivors can need some time before sex is really okay. It's also fair for you not to want to be her medicine, too, and not all that fair -- albeit human -- for her to approach you that way. trying to normalize sex again after a rape is a pretty understandable impulse: one doesn't want to thin the enjoyment has been robbed from them.