It is a truth universally acknowledged that a society in which 13-year-olds are assigned careers must be in want of a savior.
Callie lives in the City, the sole enclave of humanity (she thinks). Like all 13-year-olds, Callie has a single authorized job. In their machine-free society, she's a computer: a numbers expert. Callie's so skilled that city officials come to learn from the patterns she finds "beautiful," though she does wonder if there's more to life. On the other side of the great forest bordering the City lies the Meadow, where Jeremy is a dreambender trainee. Unbeknown to the City dwellers, dreambenders monitor their sleeping minds, snuffing out dangerous tendencies, especially the most dreaded: music. Jeremy is the "shining star" and "greatest hope" of the dreambenders (in his own words, "an inquisitive genius"), but he won't bend Callie's dream, for he's taken by her sleeping thoughts of song. He's determined to topple the dreambender regime with the help of Callie and the friends they make in the woods (including a cognitively disabled dark-skinned mute). Blonde Callie and black-haired Jeremy are both evidently white, with characters of color relegated to secondary status. Between this and the poor worldbuilding that underlies the story, the novel makes a sad contrast to Kidd’s excellent Night on Fire (2015).
There are plenty of novels about kindly-but-oppressive dystopian societies in which a child has a designated future path; skip this one. (Fantasy. 10-13)