It may seem like a long time ago but in reality it was not.

It was less than three years ago that Andrew Thomas, selected by the Giants with the No. 4 overall pick in the 2020 NFL Draft, as a rookie was not playing anywhere near the level of a franchise left tackle.

“I wasn’t performing well, and people didn’t think I deserved to be here,’’ Thomas said.

Things change. Thomas will be here — with the Giants, that is — for the foreseeable future.

Before the Giants took the field Wednesday for their first practice of training camp, Thomas cashed in.

The 24-year-old stud left tackle signed a five-year extension worth $117.5 million, The Post confirmed, a megadeal that includes $67 million in guaranteed money, the most ever for an NFL offensive lineman.

This keeps Thomas under contract — incredibly — through the 2029 season, as the Giants made a preemptive strike to lock up one of the top players at his position in the league.

“I’m a believer in it,’’ general manager Joe Schoen said of re-signing key players a year early. “He played at a high level and he’s our type of guy. To get ahead of those things, I think if he’s willing to do a deal, and it was something we were comfortable with, both parties were happy with where we ended up landing.’’

Thomas landed in quite a spot.

He received a signing bonus of $15 million, according to a source, with the next four years, plus roster bonuses, fully guaranteed.

Thomas can earn an extra $250,000 in any year he makes the Pro Bowl or is named All-Pro.

With a base salary in 2023 for Thomas of only $1 million, the Giants were able to shave about $6 million off this year’s salary cap.

“It’s a blessing to be in this position, and it’s also motivation to keep working, and to live up to that number and compete to be the best tackle in the league,’’ Thomas said. “I would say security was the biggest thing, guarantees, things like that. Especially with my history of ankle injuries and things of that nature. Playing offensive line, people falling on you every game, you want to be secure. You don’t hope for injuries, but we know that’s a thing that happens in this league.’’

Thomas called the massive contract “a blessing for my family [and] my kids that I don’t even have yet.’’

The signing comes a day after star running back Saquon Barkley agreed to a one-year deal worth up to $11 million, ending a prolonged contract stalemate.

Thomas’ struggles as a rookie created the narrative that the Giants erred with him, considering they had their pick of Tristan Wirfs, Mekhi Beckton and Jedrick Wills, three highly touted offensive tackles.

Thomas, though, proved to be the consummate pro and raised his level of performance every season.

In 2023, Thomas graded out as the third-best left tackle in the league, according to Pro Football Focus, behind only Trent Williams and Christian Darrisaw.

Thomas gave up three sacks last season in 619 pass-block snaps.

“I’m extremely happy for him and happy for myself, also,’’ quarterback Daniel Jones said, smiling. “He’s a tremendous player. He goes about it the right way.’’

The Giants shelled out big money this offseason to lock up their best young players, signing Jones (four-years, $160 million), defensive tackle Dexter Lawrence (four years, $90 million) and now Thomas.

“We have a good core group of guys, especially the younger guys,’’ Thomas said. “I love the staff. This is the most fun that I’ve had playing football in a long time so I’m excited to be a part of this organization and hopefully we can do some special things.’’

It was a matter of when, not if, as far as the Giants making sure there would be no free agency for Thomas.

His average per year of $23.5 million is the second highest in league history for an offensive lineman.

The $67 million in fully guaranteed money is the most ever for a non-quarterback first-round pick after only three years in the league.

Thomas said “that’s the mindset I have’’ when asked if he believes he is the NFL’s best left tackle.

“But I think there’s more to prove,’’ he said. “There’s definitely some things that I can clean up to be a more dominant player to have that title but I’m still working every day to get there.’’