PHOTO BY JOJO WHILDEN / PARAMOUNT

The hit comedy “Mean Girls” is only 20 years old, a relative newcomer in the comedy canon. Yet when it comes to the 21st century, it’s not the years; it’s the mileage.

2004 feels a long, long way from 2024, raising a valid question: Can a new “Mean Girls” reflect modern high-school life? Do kids still write secrets in carefully hidden diaries? Do teens still throw raucous parties when the parents go out of town? Are girls still mean?

Some are, it’s safe to say, although they probably confine their daggers to certain apps.

That’s just one of the tasks in front of the new “Mean Girls,” based in part on the original film and in part on the 2018 Broadway adaptation. It must update its references, lingo and attitudes while retaining the basic plot of the original; it must contain the iconic dialogue and moments of the first film (“You go, Glenn Coco!”) while inventing enough new humor to stay fresh; it must decide if it wants to focus on the musical or function as a gentle reboot of the film.

Most of those goals are fairly successful. This “Mean Girls” feels fresh and lively, directed with energy and verve by the team of Samantha Jayne and Arturo Perez Jr. and written, like the original, by Tina Fey. Most of the new jokes land; most of the old nods are sufficiently revitalized.

Any skeptical audience members should be thoroughly cleansed by the vibrant, fully committed performances. Reneé Rapp manages to eclipse the original film in her venomous yet vulnerable take on Regina George; she’s a major star in the making. While Rapp might earn MVP honors, the show is frequently stolen by Auliʻi Cravalho; previously best known for providing the voice of Disney’s “Moana,” Cravalho’s defiant, savvy Janis is delightful. Her fellow plastics, played by Avantika and Bebe Wood, nail the humor; Angourie Rice, as wide-eyed newcomer Cady Heron, is relatable if not quite memorable. 

“Mean Girls” is at its best in its musical sequences, which bring fantasy and blink-and-you’ll-miss-them gags into the film’s grounded reality. Only about half of the songs from the Broadway version make the cut, but those that do are the powerhouse numbers; when the characters start singing, the film leaps off the screen.

When they seem to forget they’re in a musical, the film does sag from time to time. Much has been made of the fact that this film’s marketing sought to hide that this is a musical adaptation; the current thinking in Hollywood is that musicals do not sell tickets. (A similar tack was used with “The Color Purple” just last month.) It’s not just the marketing; “Mean Girls” seems afraid to fully embrace its inner theater kid, spending long stretches in relative reality before it bursts back into boisterous fun. The film certainly isn’t bad when it plays things straight, it just gets much better when it lets loose.

Maybe that’s fitting: A movie that’s charming despite its lack of confidence, trying different modes in an attempt to fit in. Just like a high schooler, right?

My Rating: 6/10

“Mean Girls” is now playing in theaters.