well, I think its too soon to tell. If i were your sister(I wish, i had such a nice sister
)) i would wait and come a day before retrieval or even after retrieval when things are more certain. I am sure she wants to be with you to support you and help you and take care of you, but she doesnt want to travel and pay for plane ticket in addition to every thig else. is she flying?? How far away do you guys leave??