Andy Robertson was expected to be named in Scotland's World Cup squad, but he admitted it was a "huge pinch yourself moment"when he was confirmed as one of Steve Clarke's 26-man party.
The squad have flown to the United States to take part in football's biggest tournament for the first time since 1998, waved off by the Tartan Army at Glasgow Airport.
Scotland face Bolivia in New Jersey on Saturday in their final warm-up match before moving to their training base in North Carolina.
Robertson is set to lead Scotland out for their opening World Cup match against Haiti in Boston on June 14 (2am, UK time), the clash with Morocco - also at the Gillette Stadium - and their final group match versus Brazil in Miami.
"Me actually walking out on the pitch the first game? I've not allowed my brain to go there yet," the defender told Your Site News.
"I just don't like getting too far ahead. I think I'll then live in that moment when I know it's the night before and I know it's the day of the game.
"That's the way I've always worked, I never look too far ahead.
"I was pretty confident I'd be in the squad, but for me it's still a huge moment, it's still a huge pinch yourself moment that you've been called up to a World Cup squad for Scotland."
Robertson, who is Scotland's second-most-capped player behind Sir Kenny Dalglish, was just four when Scotland last played at a World Cup.
"We've got a smaller group in the group chat in terms of the lads that are my best friends, and I actually put a message in when the squad got announced," the 32-year-old added.
"I was just like 'who would have thought we would all be going to the World Cup together when we're all playing as little kids and chasing after each other as 11 and 12 year olds?' And it was a real moment of sense of achievement because it's not easy to get to a World Cup.
"I think we've proven that with how long it's took us to get there - since 1998 - but the fact that you're one of 26 going to represent your country in the biggest stage, it's a real proud moment.
"We've had some dark times, we've had some dark moments.
"In a Scotland jersey, the lows are the lowest that you'll have and the highs are the highest you'll ever have with your country because you know you're representing a nation, and that's the thing. But I think that's why our squad is so close and such a good group of lads because if you look at everyone's story, all of them are pretty similar."
Goalkeepers: Craig Gordon (Hearts), Angus Gunn (Nottingham Forest), Liam Kelly (Rangers).
Defenders: Grant Hanley (Hibernian), Jack Hendry (Al Etiffaq), Aaron Hickey (Brentford), Dom Hyam (Wrexham), Scott McKenna (Dinamo Zagreb), Nathan Patterson (Everton), Anthony Ralston (Celtic), Andy Robertson (TBC), John Souttar (Rangers), Kieran Tierney (Celtic).
Midfielders: Ryan Christie (Bournemouth), Findlay Curtis (Rangers), Lewis Ferguson (Bologna), Ben Gannon-Doak (Bournemouth), Tyler Fletcher (Manchester United), John McGinn (Aston Villa), Kenny McLean (Norwich), Scott McTominay (Napoli).
Forwards: Che Adams (Torino), Lyndon Dykes (Charlton Athletic), George Hirst (Ipswich), Lawrence Shankland (Rangers), Ross Stewart (Southampton).
