You have to get your head in the right space to read this book. It is a children's book, in the same way Lord of the Rings is a children's book. You can read it at any age you want, but if you're older than the last big shift in how your brain works, this isn't really for you. And given it is written by someone with a brain in the same space as yours, it's a little bit condescending. It's also limiting. Like there is forbidden knowledge to young minds that must not be revealed.
Beyond that limitation, this is a really good story. It is light and funny and full of farce. Holt goes wide, not deep. If you're looking for books to add to your Snow White cannon, this arguably isn't one of them. I mean, like the original fairytale, the real story is about the Queen and not Snow herself, but unlike any cannon version (except, ironically, the film Grimm's Snow White (2012)), Snow is blond. Like, how is Snow blond? She is created by a spell, requesting 'skin as white as snow, lips as red as blood and hair as black as the wood of the window frame'. The original Queen gives her life in pursuit of this perfection, the least we can do is honour her wishes. Besides, a blond Snow is Arian - this is a German fairytale.
Other than that, no notes.