Welcome to Health Care Magic
At this age, they are unstable and are easily influenced by extensive exposure - by friend, family society, media and so on..
You have to have true assessment of her actual interest and help her with it...If Music is her option, why not? But she should be convinced of the necessity for a basic undergraduate education and persist with the idea...
If the attitude is changing frequently, it may not be real interest / just an infatuation; may change again.
Make sure, she has no bad company or devious ways...
Family support is necessary.
Psychological assessment and counselling
Wishing speedy recovery