When I was a kid, we didn't have proms, we had a "leaving evening". Girls with Krystle Carrington hair for the night would bop shyly around handbags. Meanwhile, wiry young bucks wore Brylcreem and leather pencil ties, and pretended not to care about anything. (This, I might add, was in Scotland, where for the previous four years we had been taught in PE to dance gaily in ceilidhs. What on earth were we thinking? Note to time-travelling self: after Hitler, sort that out.)
It was a long way, it seemed to me at the time, from the Busby Berkeley-choreographed Versailles-like extravaganzas that Americans seemed to have at high school. But then, everything about US schools, mediated by film and song, appears to be more glamorous than British ones. It's like the difference between "woop-woop" American cop car sirens and the whiny "wee-waa" of the Anglo plodmobiles.
Sometime over the past few decades, the school dance became a prom. Although I once worked in a school where the night was called the Leavers' Graduation Certificate Ceremony, which rather misses the point: the word "prom" perfectly conveys the breathless inbetweener moment that marks the voyage from child to adult.
It's a dizzying time. Adulthood descends on some in the evening, some in the morning; some it lands upon as lightly as a dove, some it clatters over like a bucket of bricks. We lack, I think, enough formal ceremonies to mark comings-of-age. More traditional cultures swim in the things, such as Jewish bar and bat mitzvahs, where toys are put away and replaced with mortgages, responsibility and cynicism.
My own school dance was a rubicon. Bespectacled, tongue-tied, harrowed with acne and awkwardness, I would have been more comfortable in my own skin if I'd worn a frogman's suit. But for that night, I'd been building up resistance to contact lenses - weeks of nights spent blinking - so I could be free of four-eyes. My mum sprung for a haircut and a hired tux, and when I walked in, for the first time in my life it felt good to be looked at instead of merely ghastly. I was even asked to dance and, in another first, when I asked someone, they didn't say no. This was powerful, powerful magic, and it will never leave me.
I left something behind that night, like a snake shedding dead skin. It didn't change everything but it changed something I never forgot.
Schools are more than just places to learn subjects. They are that, assuredly and importantly, but they are also places where voodoo happens, voices break for ever and hearts for the first time.
Every time I go to the school prom, I remember how important it was to me, and I see my students, now no longer my students, dressed in every shade and tone of adulthood they can muster.
And we, the teachers, hang on the sidelines (note to teachers: this is where you should be. This is their night, not yours), and watch the people we helped to build, build themselves.
Plus ABBA. Game on.
Tom Bennett is a secondary teacher in East London, director of the ResearchED conference and the government's new school behaviour expert