The first millenials were born in 1981, so yes, they were definitely teenagers by that point.
Isn’t it 82? Whole reason they’re called millennials is because they graduated high school in the “new millennium”. 81 would have graduated in 99.
There’s rarely a strict cutoff for this sort of thing. If you’re on the edges, it’s sort of “whichever feels right”. I am only a year older than my wife, and we were both born in the late 70s, but I had a brother 7 years older than me and she was her parents’ first. Based on the TikToks she sends me, she identifies as a millennial. I am much more in tune with the Gen X zeitgeist.
Yeah the whole thing is just opinion and nothing official. Even Wikipedia 's definitions are based off others opinions. However to me, millennial makes sense as 82 and on being the first graduating classes of new millennium. I remember in elementary school they’d make such a huge deal about being the class of 2000.
I’ve also seen another group cut into the early 80s as the Oregon Trail generation, as a way to for people who don’t associate well with Gen x or millennials.