“Booksmart” is a sweet, funny, and insightful coming-of-age film about two overachieving young women who realize, almost too late, that they forgot to have fun in high school, that all they did was study. But there still might be time for a little partying.

If that sounds like too many other high school movies, most of which are raucous and filled with sex and drugs, relax. Among its many attributes, “Booksmart” is a class act, filled with realistic and easygoing performances - along with a couple of winningly done slightly outrageous ones. The central story, of the relationship between longtime best friends Molly (Beanie Feldstein) and Amy (Kaitlyn Dever), as well as how they - a couple of outsiders within their school - deal with their peers, is a refreshing one. And this feature directorial debut by actress Olivia Wilde is a mostly solid piece of filmmaking that keeps everything moving forward smoothly and makes sure that every character in the wide-ranging ensemble is as important as the two leads.

The script, in one form or another, has been around for close to a decade, and numerous updatings, most recently by Katie Silberman (“Isn’t It Romantic”) have put it through radical changes that have made it more current, clever, and hip.

Borrowing a bit from “American Graffiti,” it looks into the celebrations and various carryings-on of a bunch of high school seniors over one long summer night, with college looming - for some of them.

But that’s where the resemblance ends, and this sticks to being a film brimming with originality. Molly and Amy only have themselves for friends. Their hard work has paid off, and they’ll soon be leaving for Ivy League educations. Because she’s the senior class president, outspoken Molly has had to deal directly with other students and situations, but for the most part she and the far less-outgoing Amy are considered by their classmates to be unfriendly nerds who think they’re better than everyone else.

Well, yeah, maybe they do, but when they’re hit with the realization that a lot of the kids around them, who are into socializing, partying, being “normal,” are also heading to good colleges, they share a “what have we done?” moment. There are parties tonight! We’ve got some catching up to do!

It’s easy to see why Molly and Amy have long thought they’re the normal ones. The folks around them include the hunky senior class vice president, Nick (Mason Gooding), who’s kind of moronic; the self-centered but amiable Jared (Skyler Gisondo), who believes everybody loves him; and the mysterious Gigi (Billie Lourd), an excitable drama queen who somehow manages to be everywhere at once, which leads to some sparkling comic moments.

The film’s many disparate elements - and characters - eventually meet up at the big last-night-of-school party happening at Nick’s swanky home (his parents are conveniently out), where more of the comedy and much of the sudden turn to drama take place. There’s drinking and drugs (and an accompanying really weird psychedelic stop-motion sequence with dolls!) and romance. And there are some revelations about some of the partiers’ inner desires.

Wilde keeps the dialogue going at a fast pace, sometimes having people talk over one another, Altman-style, with some of the constant talking shot in extreme closeup. The only missteps are the inclusion, albeit briefly, of a couple of the parents, as they’re just not needed here, and the introduction of an uncomfortable misunderstanding between Molly and Amy - a ploy that’s used too often near the ends of films and is the only time in this one that there’s even a hint of a cliché. That part, too, is mercifully brief. In short order, the long night comes to an end, it’s graduation day, and viewers will be more than content that they’ve been treated to a story about what best friends mean to each other, and don’t care what the rest of the world thinks of them.

Ed Symkus writes about movies for More Content Now. He can be reached at esymkus@rcn.com.

“Booksmart”
Written by Susanna Fogel, Emily Halpern, Sarah Haskins, Katie Silberman
With Kaitlyn Dever, Beanie Feldstein, Skyler Gisondo, Mason Gooding, Billie Lourd
Directed by Olivia Wilde
Rated R