There's a good book on the topic called "Why We Sleep" by Matthew Walker, a professor of neuroscience and psychology at Berkley. In it, it discusses how teens are biologically designed stay up much later than their parents would, with the theory that this is when they would have a chance to socialise and mate without the watchful eye of parents. Not only that, it reduces the time that a tribe would be open to attack or prededation - if everyone slept at the same time, there would be an 8 hour window of the day where humans would be incredibly vunerable. Presumably it would be favourable to have a few adults in the tribe to have a similar night-owl streak, to keep the tribe secure throughout the night.

The book really pushes the narative that making kids, and especially young teens wake up so early just to fit into an adults daily routinee is akin to child abuse, as it stunts their growth in ways - physically and mentally - that cannot be achieved by any means except through sleep deprivation.