I'd highly recommend it for preteens and young adults, especially for girls going through puberty. But as an adult, I really enjoyed this book as well. This is one of the most unique worlds I've ever read about. There are all sorts of details that are similar to our world, but completely different in some significant way. It was lots of fun to see the world unfold.
The story is about a girl who goes on a journey to save her friend. A large part of this involves learning about the powers she's developing, and also learning more about the forest that everyone avoids because it's considered too dangerous to approach.
This book was fun, beautiful, and creative. It's one of my default recommendations for young adult readers, and I would love to see more books set in this world!