She cast the curse. I think she always knew. It would be a lousy curse if you intended it to be able to ruin people’s lives and then watch them suffer, but then didn’t remember to enjoy watching them suffer. I have to think Rumplestiltskin has better quality control on his curse-creation than that.
I do agree that in the scene in the orchard it appeared that Mr. Gold knew the score, and not just the “please,” but that when Regina asked who Emma was, Gold replied, “I think you think you know exactly who she is.” What would he mean other than that Regina suspected Emma to be Snow and James’ child who had come to break the curse. Maybe that moment planted the seed in Regina’s head that Gold knew who he really was, but it just took her a while to gather more information and decide to finally confront him about it. She probably knew that coming out in the open that he knew about the curse, and she knew that he knew, and he knew that she knew that he knew, etc. etc. etc. would take their conflict to another level. She just needed to get prepared for that before opening that can.