A day after his birthday, the magnitude of the occasion was still hitting Lamar Wallace.

“I’m looking at the balloon in my room, it says ‘Happy Birthday, 105,’ ” he said. “It’s not understandable. There’s no reason for it. It’s hard for that to sink in. How did I make it so long?”

It’s a question he increasingly gets as longevity transforms him into being somewhat of a sage, a person who has so far outsmarted the inevitability of Father Time.

The answers are largely unknown. He stopped smoking in the Thirties. He drank moderately all his life. Ditto for food consumption. He cut his own lawn until last year. And, probably most significantly, the semi-supercentenarian (that’s what they call the 105-109 crowd) picked his grandparents well.

When you are born during the William Howard Taft administration and are still around to watch Donald Trump pick his Cabinet, then you are almost certainly blessed with good genes. Research tells us that.

And Wallace fits that bill — he had a grandmother and aunt who made it to triple digits.

Less than one in five centenarians are men, so Dr. Thomas Perls, director of the New England Centenarian Study at Boston Medical Center, calls Wallace “a rarity among a rarity.”

A U.S. Census Bureau study of centenarians around the turn of the most recent century found that 6,359 of the 37,306 centenarians were 105 and older. The 2010 census found 53,364 centenarians but estimated the number of the over-105 crowd to be under 5,000.

However you slice it, there aren’t many Taft or Teddy Roosevelt administration babies still around.

On Monday, I drove to Peachtree City to attend Wallace’s 105th birthday party. The fact that he was turning 105 was interesting. But what really won me over was that he was America’s oldest living Eagle Scout.

My youngest son is expected to soon achieve that rank and I thought it would be kind of cool to talk with a guy who earned his Eagle almost 90 years ago.

The values of Scouting — clean living, honesty, respect for others, leadership — are something that stayed with him.

“I used Scouting a lot,” he said. “I used it with what I did the rest of my life. I was fair in everything I did. Or I tried to be.”

Naturally, that’s what you’d figure an old Eagle Scout would say.

And perhaps sowing good karma is another of his secrets to long living.

Part of the attraction of being as old as Lamar Wallace is you become the focus of stories. The guy bought a new Cadillac when he was 100. One hundred!

A couple of years later, he bought a pickup truck. Why not? he figured. Although he was noted for being somewhat tight, he figured you can’t take it with you. And he wanted a nice ride.

L.B. Groover, a former neighbor who is decades younger than Wallace, was a bit sheepish in telling his Lamar Story.

“I had some health problems, so he called on my wife and said that he’d cut the grass for me,” Groover said, smiling.

Carolyn Groover respectfully declined the offer. “I didn’t want a 101-year-old man cutting our grass,” she said.

Sitting face to face with a 105-year-old is a wondrous occasion to be in the presence of someone who experienced events captured in black-and-white photos in history books.

He was born in 1911 when there were 46 states. His home state of Oklahoma was a territory just four years prior. They were still working out the kinks in the Titanic. He survived the Influenza Pandemic of 1918. He experienced the Dust Bowl and still recalls the ominous clouds and reddish powder-fine silt that seeped through closed windows. He was a draftee who worked his way up to become an Army captain in World War II.

And so on. You get the picture.

He worked for decades on the Tulsa newspapers in the circulation department and later went into real estate. He outlived two wives of 30 years each but had no children, although he has three stepchildren. One of them, Rick Decker, was there celebrating the birthday at the Somerby assisted living facility where Wallace now resides.

Yep, Father Time did finally catch up with Wallace, causing him to have to give up his longtime home in Tyrone.

This year, he fell and fractured his hip bone. Normally, an injury like that can be an elderly person’s downfall. And it would have been for Wallace without an operation. If he had no prospect of getting back on his feet, then what’s the use of going on?

So doctors installed a rod and pins in his hip a few months ago and he hopes to try a walker in a few weeks.

“Amen, my God, yes, I want to walk again,” he said when asked about his goal. “First, I have to be able to stand. And then I’m gonna start practicing again, learning to walk.”

He said it with the conviction of an old Boy Scout who knows life is one step at a time.