Okay, that's--probably still impossible according to her understanding of physics, but not totally blatantly impossible actually, and anyway her understanding of physics is mostly from miscellaneous textbooks people have put on the internet, and anyway anyway none of her understanding of anything expected an intelligent self-modifying book so it's all pretty suspect at this point. At least some things that everyone thinks are impossible are possible and the only question is which. And whether the book is wrong or lying or correct. And whether she wants to go to another universe, which is scarier than any of the other questions.
It's not that she hasn't had hundreds of daydreams about going to, or being in, other universes. And it's not that she has a particularly amazing life here. Objectively speaking, she has nothing much tying her to this plane of existence at all. But her parents would be sad if she disappeared, and she'd never get to read the last Harry Potter book--unless the Harry Potter books are accurate descriptions of a parallel universe and even then that's probably not the best possible universe to live in. And going to another universe doesn't necessarily come with a house or a job or a legal identity, which is never a problem for fantasy protagonists but could still be a problem for Brenda.
She should write something. She doesn't know how to put any of that stuff into words, so she writes
Would I be able to come back here if I left?