Within 30 minutes in each direction this was the normal start time for practically all high schools in my area growing up. Where I live now my niece who I occasionally drive to school when weather is bad starts at 7:30. We need to leave her house by 6:45 to make it on time with traffic.
The reason for the absurd starting times was always explained that bussing schedules forced it. They did not want to start grade school so early, and the same busses ran routes for both. One or the other had to start 60-90 minutes before the other.
I’d sleep in my clothes and try to make it out the door to be at my bus stop by 6:40 every morning. Luckily I had a really great bus driver who knew where I’d live and if I was running late would stop outside my house and honk.
You spent the entire morning extremely tired and a lot of kids slept through study hall or classes. The early study hall was coveted for this reason - additional time to sleep.
This was pretty much every bog standard public or private (think catholic schools) high school in the area.