So Mystique doesn't know Rogue at all? Because it's pretty goddamn easy to see she wouldn't want to even risk the life of the baby to save herself. Gambit even says as much. So either Mystique didn't care what Rogue wanted or she doesn't know her "beloved" daughter at all.
Destiny foretold that Mystique would save Rogue, and that Rogue would love her again.