When she enters the university, her horizons will be broadened and there will be more choices/temptations in all aspects.
If she wants to change her mind at this time, you can't help it. You have no right to stop her from choosing someone else, do you?
If this really happens, it can only be said that the love between you is not enough, and the love between you can't resist the temptation.
After this situation, do you still think you are suitable? Is such a girl worthy of your infatuation?