I think that it just means that she is not all knowing. The Queen only knows what she always has known and she never really understood the full implication of what the curse would do to her and what it would be like. I don’t think that means there is anything wrong with her memory though. I don’t believe that Rumpel is all knowing though either. I think he just knew more about what the curse would do and what it would be like and was willing to wait 28 years stuck in time to do whatever it is he is trying to do.