She is young, so her brain is like a sponge. I don't teach using Harry Potter as I dislike the content. You need to give her as much exposure to the English version as possible. You can use books with audiobooks, and she can read along with the recording. If she has any questions, she is welcome to ask them during class. Plus, it is a big leap from the books we are currently to a novel. So, we'll read some starter novels and see how she copes.