"From chapter 17 to 25 S!@* starts to hit the fan. How-so? Well, they over use that word completely (you know the word), but this is when the characters begin to actually form and you get to see what they could be as they advance in life(even though they are in sixth-grade and some of the things they do should be what high-schoolers do). As well in chapter 24 and 25 you get to see what starts to happen to the earth and assume what will happen to all of the characters and the world they live in.
One theme to focus on is (not one in the book but i want to identify this) not that they are finding themselves, but they are doing it too fast as if they were in high-school already. I'll let gabby be an example "a lot of girls there shave their heads", now i'll give some context. Gabbie says this after making an online dating account and finding a 16-year old boy living in a real-time colony (real-timers ignore the clocks and judge time based on the sun and moons current movements in the sky) and then goes to that colony (now referred to a circadia) for three hours, and to make this all even more odd, she shaved her head either to fit in, or make him like her more for her looks instead of personality. This is not what any sixth grader would currently do (to my knowledge) because this sounds like what any teenager would do, oh yeah, did i mention there are some "pg-13" themes as well? Drinking, cursing, saying "screw it" to rules that if they disobey could kill them, and dating people way older than them (by way older I mean 12 year old dates 16 year old).
Most of the characters actions I can easily blame on the "slowing" but should be blaming on how the characters are acting like teenagers. The adults in the book are showing blatant cheating with their lovers, and simply just acting strange. The young characters have little to no authority, by which i mean the adults are focusing on their own lives, forcing our young protagonists to behave like teenagers.
Earlier in the book the character describes the economy taking a massive hit after the "slowing" causing a wide spread panic, making people fear that the apocalypse is coming and they better prepare. Society as a whole takes a pretty big hit as well, by running on an inefficient time system that does not match how slow day and night is. Society splits into real-timers, and clock-timers, most of the real-timers make their own colonies and just live with their own rules apart from clock-timer society.