Occasionally, when I’m speaking to a class of 100 18-year-olds, I make the mistake of referring to them as millennials. Then it occurs to me: these people might not even be millennials at all. Their first memories are of 9/11, if even that. (It used to be that students’ first memories were of the OJ trial or the bombing at the Atlanta Olympics. Time passes). They weren’t old enough to vote when Barack Obama was first elected. In short, they are very far from the same age cohort I’m in.

Of course, the peculiarly American obsession with generations is, as Henry Ford might have said, bunk. We obsess over generations the way we obsess over decades, as if either one was a self-evidently meaningful unit of history. The Sixties were never really the Sixties; the culture in 1961 was far more bobby-socks and poodle-skirts than Afros and love-beads, while the late Sixties had more in common with the early Seventies than either decade had with its beginning or end. The same goes for the Nineties—Nirvana versus Sugar Ray and the Spice Girls? You know how this story ends.

Yet even a decade is a more reliable and meaningful measure than a generation. At least we know how long a decade is. A generation is far harder to define, though pundits and advertisers have never blanched at the challenge. Wikipedia defines a generation as a “cohort of people who were born in the same date range and share similar cultural experiences.” Definitions of a generation might include people born in the same ten to twenty year period, yet we all know that our older or younger brothers and sisters often do not seem to be part of the same “cohort” as us culturally speaking, especially if we’re a sufficient number of years apart.

Wikipedia also tells us that the idea of a “social generation” caught on in the nineteenth century. So this whole idea that a group of people within a similar age range have a definable and distinct social experience is really not all that old itself.

So why is it that we’re so fixated on the idea of generations? I’ve always felt like there was an “off-generation”—my grandparents were too young to serve in WWII or Korea (so not the Greatest Generation, though they were pretty good); my mom was much too young to experience the Sixties; and I’m just barely a millennial. All of us were on the off-beat of history, coming too late or too early to the big party of our times.

Indeed, I say with some pride I’m a millennial. Of the available options, it seems like the best thing to be. I don’t share the Generation X experience at all, while my friends and coworkers who are in their forties definitely seem to identify with it. Less Than Zero, Singles, Friends—the people in these pop cultural products were all way older than me. (Indeed, Brett Easton Ellis’s novel came out when I was a toddler.) Then again, it’s true that youth culture is often made by people who aren’t youths—the girls who screamed for the Beatles might have been baby boomers, but John and Paul were born in the early Forties, while Friends might have dominated the Nineties, but the characters (and actors) in the show were significantly older than the teens whose “era” was defined by the show—and who watched its horrible conclusion in 2004 with wistful and unwarranted nostalgia.

In any case, I was born in the early 1980s—the outer limit of what can probably be called a “millennial.” William Strauss and Neil Howe coined or at least popularized the term, defining millennials in 1987 as the kids who were then entering preschool, and who would come of age around 2000. Yet “millennials” also have a history as a sort of add-on, the Generation Y to Generation X, the whatever is after the kids of the boomers who marketers needed to target and define in some way or another. Pundits now find themselves in the same place, extrapolating a Generation Z of folks who come after the millennials. Like postmodernism, they are a post-thing, the “iGen” or the post-millennial—a perfunctory category.

Millennials were, of course, once the same. Boomers did a lot of drugs and stopped a war (supposedly), inventing the commodification of dissent that Thomas Frank has written so eloquently about when they left the dorm rooms and joined the boardrooms. Gen Xers were thought to be cynical and lackadaisical (see Reality Bites and Janeane Garofalo’s job at the Gap, or pretty much anything Winona Ryder has been in); they were all underachievers until they invented stuff like Netscape and Google.

My ostensible group grew up long after the patchouli of the boomers faded in the mist, and the flannel of the Gen Xers was tossed with mothballs. Even cynicism was passé. Ours was the age of Clinton and Bush, of meaningless politics and reality TV—then of total disillusionment with the Iraq War, Terri Schiavo, and other nonsense. But then there was Obama, and hope. And then not-hope.

Indeed, I was on the leading edge of the millennials the same way my mom (born in 1960) was on the tail end of what could meaningfully be called the boomers. I don’t know if I’ve had the quintessential millennial experience, if there is such a thing. The media tell us that millennials are self-absorbed and lazy but optimistic. Maybe the bulk of the herd of millennials had a different experience than mine.

But here I am, a mid-30s person with a college degree and a mortgage, technically in a category that the media continue to treat as if we’re still in Garanimals. It’s hard to say when “millennial” will stop meaning “kids,” though it has already taken on the connotation of “failure to launch” cases of twenty-somethings munching on Totino’s pizzas in their parents’ basement—despite the fact that millennials are actually busting their asses for low wages to pay back the debt for the college degrees that didn’t gain them a decent standard of living.

We’re adults now, sort of. It will take a while before conventional wisdom catches up with the lived experience of actual people, if it ever does. But as the ultimate baby boomer song said:

Now for ten years we’ve been on our own

And moss grows fat on a rolling stone

Are we also “a generation lost in space”? Fear not. As long as we have another, subsequent generation to complain about, everything will be fine.  As Wilco once said, “every generation thinks it’s the worst… every generation thinks it’s the end of the world.”