Yes – this is fine. However, just because a child can read the words in a book it doesn't mean the content is appropriate. The interest level of the material must be considered. Interest level is based on content—a book’s themes and ideas—and indicates for which age group a book is appropriate. The chart below shows which years fall into each Interest Level.
Interest level year:
In many cases a book’s interest level coordinates with its book level. Many books, however, have a low book level but are appropriate for upper years and vice versa.
However, if a book isn't on the Accelerated Reader system, or there's a book that sits outside their ZPD range and they would really like to read it, we won't discourage them in doing so, but suggest that they read it as well as a book within their ZPD range.