We tend to forget just how ready-made for the job he really was, right away, right from the jump. Eli Manning has been the face of New York football for so long it’s hard to remember what that visage looked like before he arrived.

That’s not hyperbole, either. Giants fans of a certain age — say, 22 and under — have no actual memory of what it is to have another player step under center (notwithstanding the dreadful Geno Smith Experiment, which Giants fans of all ages treat the way “Dallas” treated Bobby Ewing’s death back in the day: as if it never happened). It took until Week 11 of his rookie year, Nov. 21, 2004, before Tom Coughlin made the switch from Kurt Warner to Manning.

And at first the results weren’t storybook; he lost his first six starts. But from the moment he assumed control of the Giants offense — and their soul — he understood what the job meant, what it entailed, what was required of him, what would be both his blessings and his burdens for as long as he held the gig. Not every young player Gets It; Eli Got It from the start.

“I gotta step it up,” Manning said after his very first start, a 14-10 loss to the Falcons on Nov. 21, 2004, that was a 60-minute ode to growing pains: lots of missed throws, a bad interception, some ill-timed timeouts. “When your defense plays that well and holds Atlanta to 14 points, you should win that game.”

He was also betrayed by his receivers, who dropped a number of catchable balls — Amani Toomer and Jeremy Shockey notable among the butter-fingered brigade — but even as a 23-year-old, Manning would hear none of it: “A lot of [the drops] were bad throws. I gotta be more accurate. At some points, I was throwing the ball too quickly, not getting my feet set. As the game went on, I got a feel for the speed of the game and got in the flow of things a little better.”

As the years went on, it wasn’t just the position Eli mastered, it was his place in the pantheon of the sport. And that is the standard he has set, and that the two logical successors to that throne — Sam Darnold of the Jets, and Daniel Jones, presently his backup on the Giants — will have to live up to.

Both Darnold and Jones seem to have that makeup, but you can’t ever really tell how a quarterback — above all others — will take to the glare and the glory, the clouds and the criticism. The thing about Manning is, even if you go back in his career with a fine-tooth comb, it’s all but impossible to remember a time when he didn’t handle himself — and his exalted status — with a proficiency that can’t be taught, that can only be part of your athletic DNA.

It’s hard to lead such a public life — and play such an essential position — without suffering at least one misstep. Remember Chad Pennington? He was another who seemed almost born to do this and he had some fine moments with the Jets. But he also had that one odd tantrum when he lectured Jets beat writers on what a “privilege” it was to have those jobs. Later, Pennington would recognize his folly, and it didn’t exactly brand him a bad guy. It was just a trip to the other side of the line. Almost everyone does that.

Has Manning? Ever? Even when he reached his professional nadir, a few months before the Giants went on their first championship run, when he became so turnover prone the Giants had to de-escalate their offensive game plan for a while before he regained his footing, Manning never shied from demanding accountability. Even when his starting streak was halted at 210 games in favor of Smith — yes, alas, that actually happened — he refused to lash out. He was honest, he told us how much it hurt, how disappointed he was, but all that did was show a human side we so rarely see in our athletic icons.

And Giants fans — who were already partial to him thanks to his two-Lombardi-Trophy legacy — were his for good. And forever.

That is what Jones has to face, stepping into those shoes, whenever it is that Giants coach Pat Shurmur turns the wheel over to him — this year, next year, two years from now. But it’s also the burden facing Darnold, who has every bit the level of expectation surrounding him as Manning did at the start, as high draft picks who weren’t selected by their teams to be adequate quarterbacks but franchise cornerstones.

Darnold faced a similar grindstone last year during an up-and-down freshman campaign as Manning did during his seven-game internship in 2004. Like Manning, he was eager and he was earnest, he knew enough to defer to his receivers when they made him look good and to invite the slings and arrows on himself when they didn’t.

After playing well in a loss to the Texans last year, and after a postgame greeting from no less a source than J.J. Watt in which the Texans’ star told him, “You’re going to be a great pro,” Darnold managed to keep his eyes on the quarterback’s ultimate prize, and his feet planted on the ground.

“I feel comfortable getting experience, and I feel like I’m seeing the field a lot better,” Darnold said. “I feel like our whole offense is really starting to click a lot better, getting in and out. But it comes down to wins and losses. We want to get out there and win the game. That’s the whole point of playing, you want to win.”

You could almost hear those words in Eli’s New Orleans twang if you didn’t know they were coming from the California-cool Darnold. He’s read the proper playbook. He has the tools to hold the job Manning has held the last decade and a half, on the other side of town. He’ll get first crack to see if his talent is equal to his poise while Jones gets an up-close look at Manning to start this season. And everything we’ve seen from Jones is that he has the goods, too, as long as he honors his talent as Manning has.

Fifteen years is a long time to be the face of anything. Joe Namath’s prime lasted three years or so — about the same time Y. A. Tittle had. Phil Simms had 10 solid years, though his rule was postponed by Scott Brunner and interrupted by Jeff Hostetler. Even at his best, Chuckin’ Charlie Conerly often had to share the job on his own team, first with Travis Tidwell, later with Don Heinrich, and George Shaw, later Tittle.

Eli? It’s been his face, and his crown, since the first administration of George W. Bush. Think of how much the world has changed since then. And how little of it has changed in our corner of the football world. It’s been a hell of a run, an epic run. Who’s the next man up? We’ll find out soon enough. For now, amazingly, it’s still Eli. For now.