This link says you can elect to be flying as a selectee:
I would go get a picture ID at the DMV or some other place like her school.
You could also get her a passport:
She's scheduled to fly Tuesday morning and it's a holiday on Monday.
I would contact TSA to ask. I would try to find every document to prove her identity like social security card or a birth certificate.
This link provdes a list of documents that are acceptable by TSA:
I would try and get a photo id of some sort before she goes on her trip or contact TSA. Thank you for the award.