If I have to make a strong guess of who's born first I would have to say Leia was born first because in the ROTJ when Luke asked Leia if she remembered Padme and Leia said ' A little bit she died when I was very young ' and when Luke said ' What can you tell me ' and Leia said ' Images really feelings , she was very beautiful , kind but sad why are you asking me this ' and Luke said ' I have no memory of my mother I never knew her ' , but I'll still have wait to get the book and see the film to be 100% sure . 💃