SOG is correct - relax and smile.
Best advice ever.
I have had alumni interviews where before we shake hands, the student is handing me a resume instead. And the student has their resume memorized too, trying to match their rote answers to my questions.
If they are giving away money, they want to know what kind of person are they giving money to. Also, if her essay made it past the first round to the interview, just refresh her memory on that (go to lunch with you and talk about the experience more).
The closer she is to her real self, the better she will do. The more she preps and tries to memorize verbatim, the higher the stress level. Some kids thrive on that, but some do not.