“Wow. You’re kind of old now.” That was the very last birthday-related post on my Facebook wall — put there by a 23-year-old, of course.

Now I realize that anyone who falls into the category of “middle aged” will want to slap me for publically lamenting my doomsday march toward 30, but anyone younger will understand my building anxiety as I stare down the barrel of that fully cocked shotgun.

I’ve never had an issue with my age, at least not until the passing of '80s icon (and perennial punch line) Sir Corey Haim earlier this month from *gasp* an accidental drug overdose. That lead to a conversation with CultureMap's Sarah Rufca about which Corey we assumed would bite it first, which lead to my making note of Corey “the other Corey” Feldman’s star turn as the voice of Donatello in the live action movie adaptation of Teenage Mutant Ninja Turtles, which I shortly thereafter realized was released — drum roll, please — 20 years ago today.

It took me a minute to process that. It’s been two decades since I first saw those four freaky, ass-kicking ninja Muppets tear it up on the big screen, and it made me feel old for the very first time.

For those of you who didn’t follow pre-adolescent boy culture in the late ‘80s/early ‘90s, the Ninja Turtles were the multimedia juggernaut brainchild — probably born of some wacky joint acid trip — of comic book writers Kevin Eastman and Peter Laird, both of whom I met during my childhood thanks in large part to a shared point of origin.

They lived and worked in Northampton, Massachusetts; a sleepy Western New England college town that was Austin before Austin was Austin (hence my total indifference towards Austin). I was born there in March of 1982.

Believe it or not, 1990 was a long time ago; during the twilight of the Cold War. When the Teenage Mutant Ninja Turtles film was released on March 30, 1990, Arizona, Montana and New Hampshire still didn’t recognize Dr. Martin Luther King Jr.’s birthday as a holiday. East Germany was still its own country. The sixth-place film at the box office that weekend was Joe versus the Volcano starring a marginally famous Tom Hanks (Pretty Woman, starring a previously unfamous Julia Roberts, was number two). The Hubble Space Telescope was in a NASA shed somewhere. Zack Morris was the only person under 35 with a cell phone. Few people knew about the Internet or Al Gore, the obscure Tennessee senator who invented it. Iraq was still four months away from invading Kuwait.

And yet somehow I remember it like it was yesterday, watching four dudes in rubber turtle suits kick the crap out of a bunch of extras up on that tiny screen (IMAX and stadium seating were yet another decade away) with my older brother Jonathan, and the Nowickis, our family friends who lived down the street (my mother — much to her delight — was spared from 93 minutes of live-action, silver-screen Turtle Power).

After that all sunk in, for the first time in my life I felt as though I’d witnessed enough history to feel the weight of my own. Don’t worry. The point of this column is not to wallow in self-pity over childhood lost. I’m 28 years old and fairly confident that I’m still years away from peaking. It’s about adjusting to the realization that childhood isn’t just over, but long-finished, and lives only in nostalgic remembrances like the one described above.

When I graduated from college a half-decade ago, my Old Man semi-jokingly said to me, “Don’t worry son, it’s all downhill from here.” I’m just now beginning to understand what he meant.

It wasn’t that post-collegiate life (AKA adulthood) was going to be uninteresting, but rather that the steep, treacherous climb to maturity was over; along with all of the over-inflated drama and adolescent angst (mixed with genuine self-discovery) that goes along with it.

He more or less paraphrased Winston Churchill: “Now this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning.”