Blurb from a JoCoNaut:

This book alternates from serious to silly to mysterious to ratcheting tension, as we get to know a group of teenagers and the AI who's secretly doing its best to look out for them. Come for the hilarious Government-Approved Sex Ed Teaching Computer gone wrong, stay for the lessons in just how many ways your online footprint can come back to bite you. (It might officially be YA?)

Steph and her mom move from city to city all the time: so often that her only friends are from an online forum site. Unbeknownst to the world, the site's moderator is a sentient AI who loves cat pictures and finding subtle ways of helping people. The story becomes a near-future YA thriller when a threat from Steph's past shows up to endanger them all. (This is the AI from the lovely short story "Cat Pictures Please", by the way.)

Content warnings include Teenagers in danger. Stalking. Psychological abuse.