The library has databases where you can find the age and grade levels for children's books: Novelist Plus K-8, Novelist Plus (for grades 9+), and Children’s Literature Comprehensive Database. (Note: if you are off-campus, you will need to login to access these resources.) You can also try searching online for the name of the book you're interested in + "age level" or "age range" and you will likely be able to find the information you need.