“How old is Kirk?” Paris Geller asks, when she visits Stars Hollow and meets the town’s quirkiest denizen. Rory Gilmore shrugs in reply. “You’d have to cut him open and count the rings.”

It really is hard to tell. The defining feature of Kirk—other than the fact that he has had so, so many jobs—is that he does not, strictly, have an age at all. At least, not in any of the meaningful ways that most people have, and indeed are, ages. When was Kirk born? Who were his cohorts in school? Does he identify with Generation X, or My So-Called Life, or Reality Bites? Does he know about Oregon Trail? Does he, when his birthday comes around, simply celebrate? Or does the day, rather, plague him with the vague but nagging feeling that he hasn’t achieved all the things he’d thought he would have by now, when he was younger?

Once again, it is unclear. Gilmore Girls is, for the most part, an airy fantasy of a TV show: From the gazebo in Stars Hollow’s central square to the witty banter of the town’s residents to the number of calories that Lorelai and Rory Gilmore are able to consume seemingly sans aesthetic consequence, the whole series sparkles, over its seven primary seasons, with a certain sheen of magic. About some things, though, Gilmore Girls is quite serious, and one of them is the thing Kirk so obviously lacks: age. Which is, in the show’s conception, not just a thing someone can be, but also a force that can be by turns acquiesced to and denied. Gilmore Girls, for a show about the friendship between a mother and her daughter, might be a nicely alliterative title; it is also, however, a philosophy revealed.

And, so, Kirk. Kirk, who functions in the show as a kind of mythic man-child. Kirk, of whom every adult in Stars Hollow seems to share a kind of joint custody. Kirk, whose rings are invisible, most of all to himself. He could be, by the looks of things, anywhere—and, more meaningfully, anything—from 20 to 50. And in that delightful Peter Panniness, Kirk is Gilmore Girls’s best embodiment of its own, pervasive ambivalence about age—and about the frustratingly fuzzy lines that, both within the show and beyond Stars Hollow’s borders, divide what it means to be a child from what it means to be an adult.

Gilmore Girls first aired in 2000, during a time that found many of its viewers contending with the advent of an unprecedented phase of life: emerging adulthood, the period that comes after the teenage years but before one, as it were, “settles down.” The period that came, historically, with the delay, and the increasing rejection, of married-getting and kid-having—and that is defined, above all, by wandering and wondering and waiting, by being at once “grown” and not yet “grown up.” It’s a phase of life that gave rise, in turn, to cultural anxieties about Bobos and Grups and the consequences of generations tangling with and possibly even merging into one another.

Gilmore Girls explores and largely embraces those tensions: The show begins, after all, just as Rory turns 16—the same age Lorelai was when she got pregnant with her daughter. Throughout its seasons, its broad premise has been that Rory acts older than her years, while Lorelai acts, generally, younger than hers. And the show is at its best when it finds the two characters—their physical ages and their behavioral ones—meeting, Benjamin Button-style, in the middle. All of that has helped to make Gilmore Girls a culmination of a pop-cultural moment that would lead the critic A.O. Scott to claim, a couple of years ago, “Nobody knows how to be a grown-up anymore. Adulthood as we have known it has become conceptually untenable.”

Well. Who better to embody the conceptual challenges of adulthood than a grown-up who is, in ways both petty and profound, decidedly not an adult? Who better than a gangly, gleeful man-child? Kirk—his last name is Gleason, but he is, as children usually are, known only by his first name—still lives with his mother. He still has “night terrors.” He still isn’t sure what “manliness” means, exactly. He is “still,” in pretty much every sense of the word.

Kirk once started a business to compete with children who were selling wrapping paper to raise money for their school; it never crossed his mind that the kids were neither his equals nor worthy of being competed against. He once played Tevye in Stars Hollow Elementary School’s production of Fiddler on the Roof, and he gave that role, as is his wont, everything he had—blissfully, if awkwardly, unaware of how different he was from his fellow thespians. He does jobs, but does not have a career; he has a girlfriend, but has very little idea how to be a partner to her. He seems to have no father figure in the traditional way, so turns instead—repeatedly—to Luke and, to a lesser extent, to Taylor and Jackson—for advice.

Kirk is also, in the way so many children can be, a bundle of contradictions. He is arrogant and easily wounded. He can be by turns sweet and cruel. He wants, so much, but he isn’t quite sure how to go about the getting. Played with mastery by Sean Gunn, Kirk can sometimes, in his affect, suggest the morals and aesthetics of Claymation: He is at once hard and pliable, at once superficial and sage, at once 2-dimensional and 3-.

“Mrs. Kim, my name is Kirk,” he announces.

I know who you are, Kirk,” she replies. “I’ve known you since you were 2.”

That’s no guarantee that people remember me.”

So Kirk will amuse you and anger you and, just when you get distracted by those things, break your heart a little. He will seem a cartoon, until he reveals himself to be so undeniably human. (“I took a lesson,” he says, of his stint as a skydiver. “The guy said I was a natural at falling.”) He is an emerging adult in the most anxious sense of the term: unsure, figuring things out, fundamentally in-between. Kirk is a person who is not yet, fully, a self.

All of that might make Kirk, in the end, the most still-relevant character in a show that is, to its vast credit, so full of them. More than Lorelai, who “stopped being a child the minute the strip turned pink”; more than Rory, who is so wise beyond her years; more than Paris, who is so ambitious beyond hers. Age may, in Gilmore Girls as in the world beyond, follow the Aaliyah theory: It may be, in the end, nothing but a number. But there’s a difference, still, between having an age and being an age—and Kirk is a weird and wacky and wonderful reminder of that. He is a man, but in another way, he is not. He is still looking. He is still working. He is still dreaming about what he will become, when he grows up.