The 19-year-old joined up with Gordon Strachan's squad for the first time on Monday, ahead of Wednesday's friendly in Poland, following a meteoric progression over the past 12 months.
While Robertson played at Hampden a year ago on Sunday, it was for the amateurs of Queen's Park in a 2-1 defeat by Montrose during his first full season in senior football.
A summer move to Jackie McNamara's Dundee United helped him catch the eye of Strachan and the left-back admitted a Scotland call-up would have would have been unthinkable had someone predicted it after that Third Division loss.
"I actually remember that game well, we played terrible," he said. "Nobody could have imagined how quick I have progressed, but I wouldn't want it any other way. You learn things so quickly.
"It's been a quick progression but I always knew I could do it. It was just about getting a chance. Luckily the gaffer at United gave me the chance and I think I have repaid him."
Robertson's development is all the more remarkable given he was released by Celtic at the age of 15.
"When I got let go I was devastated," he said. " Because of the age I was, I never wanted to give up. I was trying anything to be a professional footballer.
"Some people thought it was a strange move going to Queen's Park but as soon as I went and spoke to the coaches, they basically sold the club to me.
"The coaches there are second to none and they are like a professional team, although they are amateur.
"I knew if I could play well there I would get the chance to play first team at an early age. Luckily I did and there was a lot of press on the Third Division due to the Rangers scenario.
"The whole team played well against Rangers and that has obviously helped us all in our careers."
Robertson, who made 39 appearances for Queen's Park, made such an impression for United that he has been an ever-present this season.
And t hat brought his first international recognition with Scotland Under-21s.
"The first call-up for the 21s, I was delighted and the second one was my first start for them," he said. "I was just happy to concentrate on that and we are in a tough qualifying group."
And he quickly impressed Strachan when some of Billy Stark's squad were called upon to make up the numbers at a training session with the full squad.
"It was brilliant, training with players who were playing in the top leagues," he said. "That helped a lot and showed the standard you have got to be at.
"You were there to try and enjoy it. You knew you had no pressure on you because none of us were in the squad for the Croatia game. It was just the boys that hadn't played.
"But Gordon takes quite a lot of interest in training and that's probably why I'm here, because I did do well in training. Obviously my performances from United have been good enough."
Despite his ongoing rise, Robertson is not letting himself get carried away by thoughts of making the left-back position his own ahead of the Euro 2016 campaign, when Poland are one of Scotland's opponents.
Scotland have not had a natural left-back in recent seasons.
Lee Wallace has been impressive for Rangers but is struggling to get in the squad because of the level of football he is playing at, and right-footed players such as Steven Whittaker and Phil Bardsley have been employed there instead.
Robertson said: "I'm just enjoying getting called up and enjoying the experience.
"Hopefully in my older years I will be pushing for a start and trying to make it my own position but just now I am glad to be involved in the first team and learning every day.
"I watched the draw and it was a good draw, and if I keep doing what I'm doing hopefully I can be pushing to be involved.
"But Scotland have a very strong squad just now. Some have missed out and think they should be here."
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