Paul McCartney is 80.

Let that sink in.

The “cute” Beatle, that lovable longhair who, with his Liverpudlian pals, knocked ’em dead on “The Ed Sullivan Show” in 1964 and, when the band broke up, went on to fabulous solo success, has reached the age when many fear their children are plotting to put them in elder care.

McCartney is safe, at least for a while, if appearances are any indication.

He looks fit, shows no sign of needing one of those fancy walkers with hand brakes, and just before his birthday performed in New Jersey with Bruce Springsteen, a stripling of 72, and Jon Bon Jovi, barely out of adolescence at 60.

Sure, McCartney occasionally falls short on certain high notes and there may be fissures in the familiar voice but — speaking personally — many loyal fans probably can’t hear well enough for that to make much of a difference.

Most important is that McCartney, Sir Paul in his native Britain, goes on and on — the fervent hope of everyone, even those of us without so much as a single hit record or the slimmest chance of knighthood.

“He has a youthful exuberance that is ageless,” Bob Spitz, a Beatles biographer, told The Associated Press. “There’s still some of that 21-year-old boy that shines through in all of his performances.”

And isn’t there some of that 21-year-old in everyone occupying the upper-age demographic — the indomitable child-
person who shares space with the one whose knees pop when bending to permit a soft landing in an easy chair and may impulsively gush, “sure,” when a son asks, “how about a catch?”

“Absolutely. I’ll start rubbing in the Bengay now.”

There is a difference in longing — a little — for the past and wanting to live in it, wouldn’t you say?

Suffer again the peculiar torments of teenage struggle, no thanks, but, ah, that New Year’s Eve in Red Hook, Brooklyn, where, in a little upstairs rec room, we danced to “Earth Angel,” “Most of All” and “Pledging My Love,” lights dim, air heavy with Arpège and Old Spice, hearts in overdrive and the sense that, gee, here comes 1957 and the world awaits.

Memories of that sort remind us of where we’ve been and how far we’ve come, even if not yet far enough — the ones we return to like underlined passages in favorite books and margin notes that declare “Yes!” or “Exactly!” or “Someday, I hope.”

Once I was in the Rocky Mountains on a clear night, sky packed with stars, nip in the air. I’d listened to a folk singer at a roadhouse and — without much tolerance for drink — felt swept away by two mugs of Coors draft.

For a few minutes, I stretched out on a grassy shoulder along a gravel road, marveled at the firmament, searched for eternal truth, a stray soulful insight. None arriving, there was little to do but brush off, laugh at myself and hike back to the Holiday Inn where my wife and kids were sleeping.

All these years later, I can see the roadhouse, feel the soft Colorado breeze, drift again toward the extravagance of space. These days, I’d be dozing after the first beer and worried that I’d need a hoist to lift me from my roadside repose. Another time, another place, another me.

Where were we? Oh, yes, McCartney.

It must be said that our durable troubadour went beyond the expected and sang several newer numbers at the June concert in Jersey — three hours, bravo! — so this was not just the sort of nonstop nostalgia you might get from a tribute band during a five-day cruise to the Caribbean.

But back the mind races to the early Beatles stuff we heard on the “Sullivan” show. Oh, how the teenyboppers screamed as John, George, Ringo and Paul belted out “All My Loving,” “Till There Was You,” “I Saw Her Standing There” and the innocent but sly, “I Want to Hold
Your Hand.” (“Careful,” said Mom. “One thing leads to another.”)

Only a year later, the Beatles returned to “Sullivan” with a wistful number called “Yesterday.” Just kids, maybe, but the fellows knew the present vanishes quickly and past awaits. Believe in yesterday, as the boys advise. But, for today, rock on.