That's impressive. But I think we're working with different notions of suburban. For a suburban high school to have a graduating class of 500, you were presumably around a large population center? Where I grew up, that was the size of the high schools in the city (of about 120k).

My school district, an amalgamation of suburban enclaves and small towns, only had about a third of that. I think being close to a larger city means probably a more sophisticated suburban population (I don't think I'd ever met anyone who'd been to an Ivy-ish school prior to college) and larger schools, which allows for more stratified educational tracks.