What should I do? Brothers and sisters, be careful.

Maybe it's because she doesn't really want to be separated from you, but she doesn't want to go against her mother's wishes, so she adopts this passive attitude of refuge. If you really want to spend a lifetime with her, I suggest that you earn your achievements recently and then take her to calculate your life, but remember to "calculate" a good life that can be justified. And it is necessary to make both of them seem to believe it, because in the long-term consciousness, your girlfriend has a certain belief in that prophecy.