The 22-year-old began the season competing with established internationals like Blair Kinghorn, Darcy Graham, Duhan van der Merwe and Emiliano Boffelli for a place at club level.
The departure of Kinghorn to Toulouse and injuries to others, however, allowed him to make three starts for Edinburgh in December and he was subsequently named in Gregor Townsend’s squad for the Six Nations.
Incredibly, with just eight senior appearances to his name in total, Paterson was summoned to start Saturday’s showdown with France on the morning of the game after Kyle Steyn’s wife went into labour, further reducing the Scots’ back-three options after injuries to key duo Kinghorn and Graham.
Paterson responded by producing what head coach Townsend described as “one of the the best debuts I’ve ever seen” as Scotland went down to a controversial 20-16 defeat by Les Bleus.
“It certainly was beyond my pre-season expectations,” said Paterson. “Especially with the senior boys in the back three at Edinburgh, it’s unbelievable.
“In November, I was thinking ‘I’m not really getting a look with Edinburgh’, but things can change very quickly and a few guys got injured so I was kind of given an opportunity through that.
“I’ll take a lot of confidence from it. I’ve not played a lot of professional rugby so I need to build up that base of games, stay fit and crack on.”
Paterson was not named in the initial 23-man squad for the France match and only learned at 9am – five hours before kick-off – that he would be starting at full-back.
“I got a call from Gregor when I was having my breakfast and I kind of figured what was happening when I saw who was calling,” he said. “There was about 10 minutes of panic and then I stabilised and cooled down. There was a bit of nerves obviously, but I was really excited.
“Jamie Ritchie (Edinburgh and Scotland team-mate) told me beforehand ‘it’s just another game of rugby but it’s also your first cap so make sure you enjoy it’.
“I was alright once I was out there. I got minced off the first ball I caught so that got me into the game. I just kind of went for it.
“I’ve been told I overthink a lot, but when it comes to game time I manage to chill out a bit and not stress as much.”
Paterson had mixed feelings at the end of a debut in which Scotland were controversially denied what would have been a match-winning try when the officials were unable to decide beyond all doubt that Sam Skinner had managed to ground the ball.
“I was a confused boy at the end of the game,” he said. “I didn’t really know how to feel at the end. I was just gutted at the result.”
While Steyn is likely to come back into the mix for the next game at home to England a week on Saturday, it remains to be seen if Graham or Kinghorn – both of whom were initially ruled out of the first two matches of the championship – will be fit enough to return.
Asked if he felt he had played his way into contention for the Calcutta Cup showdown, Paterson said: “I’m not sure. I don’t know who is available. There’s a lot of moving parts so I’m not really sure what will happen there.”