If she has something of academic interest that she is really - really fond of (anything, a book, a piece of work etc.) and she does REALLY want to bring it with her and share the experience with an adult then let her do it. But it will have to be something she wants to bring, not you. My kid wanted to bring one thing, I did other things (or nothing because I fretted it will look pretentious) and in the end he did his thing and it worked like a dream. He came out smiling and relaxed, just like he was when he went in. I suppose this falls into the catogory of advice of the form " let them be themselves".
All the best of luck,
I would really apreciate any ideas on what this interview is like.