Saoirse Ronan is a grownup

There's a scene near the start of Brooklyn, which I just saw on Wednesday night, where Saoirse Ronan's Ellis (pronounced Eye-lish) watches a friend walk off with a cute boy at a dance in her small Irish town. Her expression toward her departing comrade, who looks back to smile and giggle, is at first one of supportive encouragement. As the girl recedes into her dance, the expression becomes by degrees more hollow, slackening into disenchantment, then dissatisfaction, then disillusionment, then discomfort, then awareness of discomfort, then a resolve that it's time to walk away and do something else. In this one 20-second shot, Ronan has given us a mini master class on acting.

This is not how a 20-year-old acts. This is how a grownup acts.

In fact, when principal photography on Brooklyn began on the first day of April in 2014, Ronan was not even 20 yet. She was 11 days shy of that birthday.

Actors who show absolute command of the craft at a young age are not total anomalies. One family, the Fannings, even has two such actresses, with Elle possibly being even better than Dokata. But there is something so prepossessed about Saoirse Ronan that it seems to put her in a different category. She was an adult even when she was a child.

I remember my first experience with her in Atonement, which it's hard to believe was nearly ten years ago now. She would have been only 11 or 12 at the time that was filmed, and though she was playing a child making bad decisions -- fatal decisions, in fact -- she was making them in adult ways. Making them with a kind of prepossessed shrewdness, which made them seem calculated rather than careless. There was something old and wise about the look in her eyes, something that indicated she'd be better off tried as an adult than a child in a court of law.

Recognizing the unmistakable presence she brought to her work, Hollywood of course targeted her for a number of familiar type teenage roles in movies aimed squarely at that demographic, things like City of Ember and The Host. But many of her roles were in projects that were a bit more challenging, making a bit more unusual use of a girl in her teenage years, like The Lovely Bones, Hanna, Byzantium and How I Live Now. I haven't seen all of these movies and some I am judging on a vague perception only, but all of them, in their way, seem to require someone with a certain maturity and sophistication. A maturity and sophistication Ronan had long before she had any business having it.

In some of those roles, there is an explicit sense of adulthood to her character. In Hanna, for example, she has been raised as a lethal weapon, a fighter who can incapacitate an adult despite her tender age. In How I Live Now, she's a surrogate mother looking after younger siblings in a post-apocalyptic England. In Byzantium she's, well, a vampire. The oldest of the old -- eventually if not now.

In Brooklyn it feels hard to imagine her as anything other than a fully grown, fully blossomed human being. Ellis the character is no older than Ronan is, but she travels on her own to New York to start up a new life. Both the decision to go and the going by oneself are signs of adulthood, but it's the stolid way she handles everything that comes her way that truly distinguishes her as a grownup. This is not to say she doesn't succumb to the occasional bouts of overwhelming homesickness, which crack her professional facade at her job. But there's nothing childish about her homesickness -- it's the mature pangs of guilt and fondness over a sister and mother she left behind in the old country. When she begins a courtship with a handsome young Italian plumber (Emory Cohen), and begins progressing with him at a rate that might seem impetuous, she's making pragmatic choices here too. Even though she feels swoony, she behaves practically, at one point even telling him that she will commit to two movie dates with him -- "even if the first one goes terribly, I'll give it another go." Sensibility incarnate.

An argument might be made that the best young actors show us what it's truly like to be a child, remaining in close contact with the turbulent emotions of that age. There'll be time enough later for them to show us how grown up they can be. Hailee Steinfeld is an actress who excels at that type of thing.

But an actress like Saoirse Ronan reminds us, refreshingly, that young people are just adults who are not yet fully formed -- or sometimes, are fully formed. The truth in her performance is that she plays characters with a kind of preternatural wisdom -- a wisdom that we believe because it can be just as true to life as characters who are changeable and petulant.

It'll be interesting to see what she's capable of when she really is a grownup.