Some kids will love it, some may find disturbing.
Parents need to know that this story has a genuinely twisted flavor that some children will love and others will find disturbing. Luke is exceptionally brave and enjoys being a mouse (in the movie, he is changed back, but in the book, he stays a mouse). Children may be upset not only by the witches, but also by the death (offscreen) of Luke's parents and his seeming indifference to it.