When I looked for books to load on her Nook at the right "reading level" they were much too mature for her age level. She is mature, but I am still having challenges finding books that will help her reading level continue to advance but that still keep her interest. She loves Junie B. Jones books, but that level is too easy for her.
That's great that your daughter is enjoying reading - that is something you want to continue to foster and nurture! Your best bet is to go to your public library and consult with a librarian who can guide you to certain 'classes' or 'levels' of books based on your daughter’s interest and reading level. Then, you can begin to assess if the reading and maturity level of the books are appropriate for your daughter. With the names of the authors and the titles of the books in hand, you can then return to your Nook and find those titles to load.