The original 2004 movie “Mean Girls” contained something unusual, both then and now: a main character who was home-schooled. But not that kind of home-schooled.

“I know what you’re thinking,” Cady Heron (Lindsay Lohan) tells us in voice-over. “Home-schooled kids are freaks.” The movie cuts to a tiny bespectacled girl spelling “xylocarp” at the National Spelling Bee. “Or that we’re weirdly religious or something,” Cady continues. A family of boys in suspenders appears; behind them are sandbags displaying paper targets with human outlines. “And on the third day,” one of the boys drawls, “God created the Remington bolt-action rifle, so that man could fight the dinosaurs. And the homosexuals.”

“Amen,” his brothers chime in.

It was a funny bit no matter who you were back in 2004, dependent on Bush-era perceptions of home-schoolers as, well, weirdly religious, survivalist freaks who insisted that God made the world in six days around 6,000 years ago. Like everything in “Mean Girls” — and, indeed, Tina Fey’s entire body of work — it was an exaggerated caricature based on a kernel of truth. Home-schooling in the 1990s, at least in the United States, was largely insular, and mostly the purview of conservative evangelical Christians with views that could appear extreme even to others in the same pew.

I was a junior in college when “Mean Girls” first hit theaters, and the joke tickled me because I’d spent the last few years trying to figure out hierarchies myself: I’d been home-schooled, just like Cady.

Well, not just like Cady. I left my private school after the fifth grade to be home-schooled, and a number of the communities my family dipped into along the way were similar to the gun-toting, dinosaur-loving kids from the movie. (The first time I really felt like my youth was represented onscreen was last year’s documentary series “Shiny Happy People.”) I went to seminars where we were taught that dinosaurs did roam the earth at the same time as humans, that the fossil record was designed by God to mess with scientists, and a whole lot of other things.

Yet I was lucky. I knew home-schoolers who had found themselves left behind academically or, worse, abused and neglected by parents. But others, like me, had a largely positive experience. My family was never as extreme as the caricatures, and I received a good education that served me well when I finally started taking SATs and applying to colleges.

But as many home-school alumni of my generation will tell you, if you grow up to spend your life in more mainstream society, there’s always some bit of you that feels different, a whole lot like Cady. A song comes on at a party or a ballgame, and everyone sings along, and you have no idea what this song is. You see long button-down denim skirts come back into fashion and know, in your heart of hearts, that you absolutely cannot bring yourself to ever put one on again. (Search “home-school chic” on social media to find out why.)

And most important, everything you know about American high school comes from Hollywood. High school movies educated me on what my peers were going through, movies like “10 Things I Hate About You” and “Clueless” and “Never Been Kissed” and “Bring It On.” Later I’d branch out to the films of John Hughes or TV shows like “Freaks and Geeks.” From them I learned some valuable lessons. Cafeterias and gyms are dangerous places. Teachers and parents are mostly irrelevant cringefests. Dances form the apex, or nadir, of your year. And everyone is forced to sort themselves into cliques to survive.

The moral of every high school movie is basically the same: don’t judge a person by her appearance, and don’t be a stuck-up snob or something terrible might happen to you. “Mean Girls” was the valedictorian of the genre: funny, quippy, infinitely quotable, larger than life and yet authentic to it. When I later became a college professor, the only movie I could guarantee students a generation younger than me had seen was “Mean Girls.” It had that kind of staying power.

In its newest iteration — a 2024 movie adaptation of the “Mean Girls” Broadway musical, in turn based on the 2004 movie — “Mean Girls” has not changed a whole lot. There are songs now and videos shot in portrait mode. There are more queer kids and more kids who aren’t white and Damian now drives his grandma’s mobility scooter instead of a car. But Tina Fey is still teaching math (and writing the screenplay), Tim Meadows is still the principal, the feminism is still a tad wobbly, and fetch is still not happening.

Home-schooling, on the other hand, has changed drastically over the past few decades, evolving from a fringe choice to a mainstream one. That’s reflected in this new “Mean Girls”: the dinosaur kids are gone, replaced with a quip from Fey’s math teacher about home-schooling representing an innovative way to take money away from the teachers union. There are still plenty of my kind of home-schoolers out there, but many more who come from other identities and subcultures and have other reasons for making the choice. Yet home-schoolers still rarely pop up onscreen as more than a punchline or bit part.

That’s why it was so funny when the new “Mean Girls” reminded me that Cady is a home-schooled kid until she returns to the U.S. When I watched the original, I mostly forgot about that part. The fact that she’d grown up in Africa, where her parents were doing field work, seemed far more important to the story and to Cady’s awkward attempts to fit into the American high school hierarchy. Lohan — who was wonderful — never quite projected what can only be described as home-school energy. She had the look and affect of someone who was pretty comfortable in a classroom, right from the jump.

The new Cady, played by Angourie Rice, feels much more familiar. She’s clad in the same flannel and jeans that Lohan wore at the start of the original, but Rice embodies a certain mousy awkwardness I recognized as my own: a desperation to watch and learn and avoid embarrassment at all costs. She might, like me, have missed the jokes and double entendres flung around by more worldly kids, and she’s definitely cautious in her approach to her new environment.

This is how I learned why “Mean Girls” as a story works so well. Nearly all high school movies operate as fish-out-of-water scenarios, the better to show off the hierarchies and sorting mechanisms that govern our lives, even when we’ve graduated and moved on.

But a home-schooled protagonist is the ultimate way into this kind of tale, because when you’re home-schooled, those structures just don’t exist. And without them, you’re a free agent. You don’t naturally belong anywhere. That can lead to a strange kind of floundering when you do the work, laid out so neatly in high school movies, of figuring out who you are; it makes more sense to take on other people’s identities than to find your own. Lacking a lifetime of being pushed into one group or another by your peers, you’re a little unmoored. That is mostly a good thing in the end, but it’s confusing and chaotic in the moment. “Mean Girls” excellently evokes that feeling, with a protagonist who is co-opted by two different groups for their own purposes.

Of course, Cady finds her way. We all do … eventually.