FLORHAM PARK, N.J. — Jace Amaro finally has grown up.

There is an urgency in his voice, a level of maturity that was missing when he arrived in the NFL. The Jets tight end readily admits he never understood the importance of doing “the little things.” But thanks to a shift in perspective, he’s attacking this preseason with astute focus.

A shoulder injury robbed him of the chance to play football last season, and the deaths of close family friends — along with a tragic accident involving the 9-year-old son of another family friend — reminded him that life is precious and that playing football is a gift he no longer can take for granted.

He isn’t the same rookie who once was more concerned with late-night outings and fast food. In his third year in the league, Amaro is determined to prove he’s a different person and an even better player.

“You shut the drinking out, you take out the late nights, you get more sleep, it’s going to pay off in the end,” he told Newsday yesterday, almost a year to the day after he suffered a torn labrum in a 23-3 preseason loss at Detroit on Aug. 13, 2015.

These days, Amaro can be found in his basement catching tennis balls — “a thousand of them,” he said — from a machine that shoots them out “every two seconds.” He’s content staying home most nights. His weekends have been pretty tame, too, he said, mostly working out at the team’s facility and eating healthy.

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“It’s been all football for me,” said the 2014 second-round pick out of Texas Tech.

Maintaining that level of commitment hasn’t been easy.

“It’s tough,” he said, laughing. “You want to go hang out with your friends, but at the same time, all I could think about is: This is my year.

“This is the year that everyone’s counting on me,” added Amaro, who in 2013 set an FBS record for yardage by a tight end with 1,352 on 106 receptions. “This is supposed to be my breakout year. So [those distractions are] just so secondary to me.”

The hard work appears to be paying off. During practice yesterday, Amaro hauled in a touchdown pass from Ryan Fitzpatrick in triple coverage. In Rob Gronkowski fashion, he spiked the ball in the end zone.

“I feel like I’m a lot better now, obviously, than I was my rookie year,” said the 6-5 Amaro, who weighs about 258 pounds.

“It’s really just all the small things,’’ he said. “And not getting so emotionally unstable when the coaches get on me. If you mess up, it’s not the end of the world. I was timid to make mistakes my rookie year. Now I feel a lot more loose out here. Especially at the receiver spot, my rookie year, I was thinking more like, ‘Where do I have to run this route at?’ instead of ‘OK, I have to beat this guy.’ And that’s what I’ve been doing and I feel really good about how I’ve been running my routes.”

Confidence never seemed to be an issue for the former Texas Tech star, who after being selected 49th overall declared that he should have been the first tight end drafted. Although he still believes that, Amaro admitted, “I don’t think I prepared myself as well as I could have physically and mentally going into OTAs my rookie year. I know what it takes now.’’

The shoulder injury not only took away an entire season but cost him the reps needed to build chemistry with Fitzpatrick. But Amaro believes “missing last year probably was the best thing that happened to me. It helped me grow up a little bit quicker. That’s what I needed and that’s what happened.”

He’s determined to showcase his talents this season, not only for the Jets, but also for family friend Luke Siegel. On July 28, 2015, the boy — the son of former Texas Tech tennis coach and Manhasset native Tim Siegel — suffered severe head trauma and skull fractures in a golf cart accident in Lubbock, Texas. Luke, now 10, remains confined to a wheelchair.

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“He’s a big reason why,” Amaro said. “It’s just things like that that kept me going every single day.”

Amaro has learned his lesson, albeit the hard way. But he’s eager to prove he was worth all of the hype in 2014.

“I just want to play so good on Thursday that it’s like ‘I’m back,’ ” he said of the preseason opener against the Jaguars. “Scoring a touchdown or even just catching one ball would be awesome. I want it to be inside. Saying, hey, I did this. I tore my shoulder. I went through all that. And now I’m back.”