You don’t have to be an extrovert to do a good interview.
Come up with a system - for example, STAR.
Situation, Task, Action, Results.
Come up with a few ideas -maybe a project you worked on or a team you were part of (or led) or a conflict you had with someone. Or a bad grade you were getting and how you recovered - just so you have thoughts.
Also, a favorite class and why and least favorite and why.
Four or five examples of things. This way, in her mind, if a question is asked, she’ll likely have at least thought of - this might work or might be good. Just a little pre organization.
Listen intently to the questions being asked.
Repeat them back - so my favorite class is…
Try to be concise, eye contact, and they’ll be fine.
Most interviews are neither make or break…but also come with questions - if it’s an alum, about their time at the school, for example.
If it’s on the website, don’t ask it.
No reason not to interview though - she’ll be fine - it likely won’t be the reason she doesn’t get in - unless she curses, wears a t shirt or does something else unprofessional, etc.
Good luck to her.