Huh, I'd liken school in those grades to a series of meetings basically all day, that are mostly presentations, every day of the week, with a lot of restrictions and harsh conduct & expectations from the people leading the meetings, which'd never fly in an office. Often with terrible lighting and long stretches without seeing the outdoors, even though a window. And crazy-early start times that may have you not seeing the sun until 3PM or so, for months. And, especially toward the end, a couple more hours of work at home every day. Mostly of math problems.

Also, all that, plus you're not getting paid for it.