Luke decides that baby!Rey will be safer with him. When he leaves he take her along. 15 years later Poe Dameron comes to the island to beg Luke to help the Resistance.

+ Rey doesn't have to be Luke's biological daughter
++ Finn still helped Poe escape and was still injured fighting Kylo Ren
+++ Rey is very excited to meet her Aunt Leia after all the stories her father has told about his past (she has always been her fave)