First priority for me would always be the major. She has to do something she really wants to. If from day 1, she is thinking about how she can move from one major to another, then everyday will become stressful. And every moment, thinking of the compromise she made to be at a particular place. Nothing is worth that stress.
In addition, if she does not like to compete with others, a high competition environment wouldn’t be good for her. Mental health is often overlooked. And I always tell myself, it has to go wrong only once. That scar is for life. I have heard of numerous cases of burnouts, depression, kids unable to compete and changing majors… These environments are not for all.
Bottomline, the question I always ask is “Would she be happy and would she thrive in this environment, doing the major she is”.