Invariably funny and inexpressibly moving in the way it looks at a young girl’s journey from innocence to experience, “An Education” does so many things so well, it’s difficult to know where to begin when cataloging its virtues.

What’s easy is knowing where you’ll end up, which is marveling, like everyone else, at the performance by Carey Mulligan, the film’s irreplaceable centerpiece.

With just a few film roles behind her, including flighty Kitty Bennett in the Keira Knightley-starring “Pride & Prejudice,” Mulligan seizes the character of 16-year-old Jenny in a once-in-a-lifetime way.

The notion of the single performance that creates a star overnight is surely one of Hollywood’s biggest clichés, but this is one time when you can take it to the bank.

That might seem ironic because there is nothing Hollywood at all about this British independent film written by Nick Hornby from a sliver of a memoir by journalist Lynn Barber and co-starring American indie stalwart Peter Sarsgaard.

The director is Denmark’s Lone Scherfig, who has an unerring instinct for illuminating the quirkiness of human nature.

There’s a magical, almost kismet-esque quality about the way all these talents came together and meshed with the film’s perfectly cast co-stars, including Alfred Molina, Cara Seymour, Dominic Cooper, Rosamund Pike, Olivia Williams and Emma Thompson. If one element had been different, the magic would not have been the same.

Everything starts with Barber, who wrote a brief memoir for the British literary journal Granta about her circa 1961 teenage affair with a man more than 20 years her senior.

That sounds unsavory and distasteful at best, but it is to his great credit that when Hornby read the piece he immediately recognized what he calls the story’s “unusual mix of high comedy and deep sadness” and ended up doing the screenplay.

As someone who comes to England from another country and another culture, Scherfig worked hard with production designer Andrew McAlpine and director of photography John de Borman (winner of Sundance’s cinematography award) to get the details of the London suburb of Twickenham in 1961 just right, focusing on a time when things were staider than staid but there were hints that change was in the air.

More than eager for change of any kind is 16-year-old Jenny (Mulligan), a student at a genteel London girls school who’s impatiently looking forward to a future that includes a place at Oxford and the chance, in Hornby’s beautiful phrase, “to talk to people who know lots about lots.”

A passionate Francophile who knows Juliette Greco lyrics by heart, Jenny is looking forward to other stuff as well, to being able, for instance, “to smoke, wear black and listen to Jacques Brel.”

She also wants to be free of her striver parents, unerringly played by Molina and Seymour, who if anything are more determined for her to get into Oxford than she is.

It can’t be overstated how completely Mulligan inhabits this role from her first alive moments on screen.

Her Jenny is a young person exactly on the cusp of adult life, bright and intelligent but inexperienced and desperately wanting to be a sophisticate. Her pure, joyful excitement at the possibilities of what she sees before her is so palpable that it’s impossible not to be on her side, impossible not to sign up for whatever journey she’s going to be on.

The journey begins when a torrential rainstorm introduces Jenny to 30-something David (Sarsgaard).

She is walking home, cradling her cello against the downpour, when he pulls up in his ultra-smart Bristol sports car.

He tells her with a smile that she shouldn’t take a lift from a strange man, but adds that he’s a music lover and proposes that she put the cello in the car and walk alongside and chat. How could she resist?

That scene, brief though it is, introduces the elements that make resistance futile and leads to a burgeoning relationship.

For one thing, David has an almost uncanny knack for saying the right thing at all times to all people, and he knows instinctively that what Jenny wants most of all is to be treated like an equal, to be spoken to as the adult she would so like to be.

“An Education” also understands that we have to see all this through Jenny’s eyes, have to see most of all how genuinely alluring David is. Played with enormous charm and genuine affability by Sarsgaard, David reminds us that seducers in real life are not as obvious as they often are on film, that they succeed because they project a palpable sincerity that at least initially does not seem open to question.

Mulligan is exceptionally empathetic through all these changes, gifted with the ability to make us believe in Jenny as an innocent, Jenny as a person of experience and all the Jennys in between.

This is a performance, and a film, to cherish for this year and always.

An Education

* * * * *

Director: Lone Scherfig

Cast: Carey Mulligan, Peter Sarsgaard, Alfred Molina, Cara Seymour, Dominic Cooper, Rosamund Pike, Olivia Williams, Emma Thompson

Running time: 1:35

Rating: PG-13 for mature thematic material involving sexual content

Where: Grand Cinema, 606 S. Fawcett Ave., Tacoma; showtimes, page 15