What, us worry?

The Jets were borderline incredulous Friday when the topic of Sam Darnold’s age was broached. As if having the youngest Week 1 quarterback in the NFL since the 1970 merger — at 21 years, 97 days, Darnold will hold that title when he takes the field against the Lions — shouldn’t be a concern. At least not when he’s a player with the skill set, maturity and leadership qualities Darnold has exhibited.

“I’m starting him — my confidence level has got to be pretty high,” coach Todd Bowles said flatly following practice. “He’s [been] playing football his whole life. We don’t go by age.”

Offensive coordinator Jeremy Bates had a similar response, telling The Post as he walked out of the interview room: “Hey, [Rams coach] Sean McVay was the youngest coach in the NFL. He’s done pretty good.”

Darnold, the third-overall pick in the draft out of USC, has impressed coaches and teammates from the time he walked onto the practice field for rookie mini-camp in early May. So much, that when asked to pinpoint a moment when he felt Darnold could beat out Josh McCown and ex-Jet Teddy Bridgewater for the job, Bates alluded to his time with the other rookies. He was that sharp right away.

“He dove right in and he mastered the three days of that playbook,” Bates said. “Ever since then, there hasn’t been any looking back, as far as what we expect of him and what he’s proven. “I think it’s just work hard, both in the classroom and on the field. He’s very humble and he’s a perfectionist. I think at the end of the day, what’s a leader? You have to be yourself. He’s himself every day. He doesn’t change. He’s very flat-line as far as his personality. He’s kind of just been Sam, and naturally he’s a natural-born leader.”

Nevertheless, Monday will still be a new experience for Darnold, his real introduction into the NFL. It will all be new, facing a first-team defense for more than a handful of series, seeing defensive schemes he hasn’t seen before, exotic blitz packages and complicated zone defenses.

“Just understand that there’s 10 other guys on every single play,” Bates said, describing the message he’s hammering home. “Football, that’s the art to it. It takes 11 guys on every play. We have to work together as a team, as a unit. It’s not just one guy. It’s 11 guys on every play.”

Bates declined to say if having such a young quarterback will limit how aggressive the Jets are willing to be in their play-calling, if they are comfortable throwing the ball all over the field if they get behind early.

In three preseason games, Darnold averaged just 5.4 yards per completion. He attempted few deep passes. Then again, teams rarely show their full arsenal in the preseason, the offensive line wasn’t whole and Bates pointed to how fast Darnold moved the Jets down the field in his first game against the Falcons, going 64 yards in 10 plays over 1:45 that culminated in a touchdown pass.

“He’s our starting quarterback, and we’re comfortable he can handle everything,” Bates said. “I think obviously we want more yards, but at the end of the day, we have to manage the game as far as the quarterback plays. We cannot turn the ball over, No. 1, we have to throw completions, and we have to stay on schedule. We have to give our defense a good chance with field position also…

“What’s the situation of the game? Are we up by some points? Are we down by points? Really stats, at the end of the day, I try not to look at them. To me, the most important thing is wins and losses.”

That’s what Bowles has said since naming Darnold the starter. He gives the Jets a “good chance” to win on Sundays, or in this case, Monday. His age wasn’t a factor, and it’s not a concern.

After all, the expectations the Jets have for him seem simple.

“Play well and win the game,” Bowles said.