The Very Secret Society of Irregular Witches by Sangu Mandanna

A warm and uplifting novel about an isolated witch whose opportunity to embrace a quirky new family—and a new love—changes the course of her life.
As one of the few witches in Britain, Mika Moon knows she has to hide her magic, keep her head down, and stay away from other witches so their powers don't mingle and draw attention. And as an orphan who lost her parents at a young age and was raised by strangers, she's used to being alone and she follows the rules...with one exception: an online account, where she posts videos "pretending" to be a witch. She thinks no one will take it seriously.

But someone does. An unexpected message arrives, begging her to travel to the remote and mysterious Nowhere House to teach three young witches how to control their magic. It breaks all of the rules, but Mika goes anyway, and is immediately tangled up in the lives and secrets of not only her three charges, but also an absent archaeologist, a...