I would say there is a 99.9% chance that all will be just fine. TSA will likely ask name/age/date of birth or something similar. They might ask who she is traveling with. As long as they don’t detect anything unusual (which they shouldn’t) there should be no issue.

But, if you want to eliminate that 0.1% chance, just do a simple letter from both parents (if possible) and have it notarized.