Mostly, yes! At home rereading is an incredibly positive thing for a child to do. Rereading is comforting and reading should feel comforting, especially at home. Second, a child does a lot of work on rereading: the first read may be just to experience the plot and then the second, third and more readings are ways for the child to explore more deeply lots of different aspects of the book, everything from understanding the character better to absorbing all the cool things about language and grammar. But sometimes a strong impulse to reread means it’s time to refresh the home library and to give your child a chance to add to their experience with a new and exciting title. But the main thing is not to judge your child: most of the time, rereading is very natural and actually a very good thing for the child’s growing brain.