Six Nations: Furlong has made huge strides since his nervy day out at Twickenham
So callow are some of the squad that Joe Schmidt has turned into Six Nations champions that, with just 25 caps to his name, Tadhg Furlong already seems like one of the older heads.
While that's what being a Lions Test tighthead will no doubt do to your profile, just like the young guns Jacob Stockdale, Garry Ringrose, James Ryan et al, tomorrow's Grand Slam decider against England (2.45pm kick-off) will be the Wexford man's first Six Nations game at Twickenham.
He had already made his Ireland bow before this fixture two years ago, but the duty of anchoring the Ireland scrum that day went to Mike Ross and then Nathan White as Eddie Jones' side ran out 21-10 winners en route to a Grand Slam of their own.
Unlike the rest of Ireland's new breed, Furlong does have experience of playing on the cabbage patch though, having won his second cap in a World Cup warm-up in 2015, and even with the biggest of prizes on offer tomorrow afternoon, the 25-year-old doesn't believe the nerves this weekend will compare to butterflies in his stomach back then.
"I came off the bench pre-World Cup to play loosehead which was an interesting experience, with Mike Ross at tighthead, me at loosehead and Nathan White at No.6 packing down behind me," he recalled with a laugh. "It was a bit of a weird one really.
"Probably looking back, I don't think I was ever as nervous before a game of rugby as I was before that one. It was only my second cap. I had learned loosehead in the space of a week, a crash course from Cian Healy, pushing my hips into walls and stuff, weird scrummaging drills.
"Also then at tighthead you know your role and it doesn't change a massive amount around the pitch, but you are in a different position in the lineout, where you go and different phases, it changes completely.
"I remember just racking my brain, looking at my notes, thinking over and over again trying to get it right."
England's loosehead that day, Kieran Brookes, is one man who could be forgiven for failing to predict that the young man struggling with his bind in the opposing scrum would soon be one of the best No.3s in world rugby.
"It's actually a funny story," Furlong said of his brief foray across the front-row. "So I was scrummaging loosehead, and I actually bound over the tighthead. So usually the loosehead binds under and the tighthead binds over the loosehead's bind then. But I bound over the tighthead's bind and (Brookes) said, 'Mate, you know you're playing loosehead, yeah?'
"I just said, 'Oh yeah', so we reset that one and went again."
Changed times for Ireland, England and of course Furlong.
Despite missing one game through injury in this campaign, the New Ross RFC man has once again proved to be an integral part of Schmidt's operation, a side that has wrestled back the Six Nations crown after two years in the hands of England.
The two sides came into this Championship amid much hype that both would be gunning for Grand Slam glory come the final day, only for England to lose on the road to both Scotland and France.
Indeed, it's almost an exact role reversal from 12 months ago when Ireland, out of contention having lost twice away from home, upended champions England to deny a Grand Slam at the last hurdle.
Furlong doesn't remember having added motivation to deny a clean sweep that day, nor does he expect England to be going out with spoiling a party foremost among their thoughts.
"It doesn't come into the players' mindset at all," he said, drawing on last year's Dublin clash. "It was a massive game against England in the Aviva with something to play for.
"It's a dangerous thing to try and get in their heads and try to second guess what they are thinking. They are coming off the back of two defeats, back at home in Twickenham."
Having played in a Lions decider in New Zealand this summer, Furlong is one of only a handful for whom there can be any argument over whether this is the biggest game of his career, but he admits that he'll try to treat the next 24 hours as he would any other day.
"I know this sounds incredibly boring but you just need to go through the same process you do for every other game," he said. "Obviously with the game that it is, you mightn't be consciously thinking of it, but around the place there is that extra buzz.
"You do nothing different, your build-up is the same, the way you prep, the week is structured, there is nothing out of the ordinary, there is nothing different, there is a game at the different with a lot of on the line."
At least he knows he'll get to stay on the right side of the scrum this time.
Ireland: R Kearney; Earls, Ringrose, Aki, Stockdale; Sexton, Murray; Healy, Best (capt), Furlong, Ryan, Henderson, O'Mahony, Leavy, Stander.
Replacements: Cronin, McGrath, Porter, Toner, J Murphy, Marmion, Carbery, Larmour.
England: Watson; May, Joseph, Te'o, Daly; Farrell, Wigglesworth; M Vunipola, Hartley (capt), Sinckler, Itoje, Kruis, Robshaw, Haskell, Simmonds.
Replacements: George, Marler, Cole, Launchbury, Armand, Care, Ford, Brown