Despite us not having anything princess-y or watching such things, Charlotte has decided she is a princess. When we went to the library, she insisted she only wanted princess books, and so I searched for books that had princesses who were strong characters, not just pink and frilly.
I came across Princess Chamomile's Garden by Hiawyn Oram and thought it fit the bill. Princess Chamomile is a mouse princess. While helping Melchior, the palace gardener, she is inspired to design her very own garden. In the process, she not only designs it, but convinces her parents and nanny that she can work on it herself.