Rhaella Targaryen did not give birth to one baby girl on Dragonstone. She gave birth to triplets: a boy and two girls who have walked and flown this world before.

Rhaegar won at the trident but that did not stop the game. Years after Robert's rebellion new rebellions accured. As the Targaryens fought to squah uprising and rebellions, the North was in it's own civil war between house Bolton and house Stark. The Targaryens finally have complete control but than they receive a letter from Jon Snow, king in the north. (There is no prophecy)