School should start at 10am.

During puberty, adolescents become sleepy later at night and need to sleep later in the morning as a result in shifts in biological rhythms. ... The combination of late bedtimes and early school start times results in most adolescents not getting enough sleep.If middle- and high-schoolstudents are allowed to wake up later in the morning, they'll be more focused during the day, more alert behind the wheel and less likely to be late to (or absent from) school.