But he never knew exactly how good he might become. And, a couple of weeks shy of his 18th birthday, he still does not know. What he does know is that he is getting better by the month.
It is just as well that the Livingston teenager is so laidback and unflappable. Otherwise he might have become quite unnerved by the surprises he keeps giving himself.
Let’s go back to last August, when Benson was preparing to represent Scotland at the Commonwealth Youth Games. “I have an outside chance of making the Olympics,” he said then.
That was not false modesty, but a realistic assessment. Only the top two in each event at this year’s British Championships in March would qualify for the London Games, and in the 100 metres breaststroke he was some way behind both Daniel Sliwinski, the UK’s No.1, and Scotland’s Michael Jamieson.
But he split the two to claim second behind Sliwinski, and is now ranked ninth in the world at the distance. That might suggest he still has no more than an outside chance of a medal, but, with just over 100 days to go, Benson is devoting every spare minute to training, in the aim of getting as close as he can to the podium.
“I’m going to aim as high as I can,” he says. “I’m going to aim for a medal, because even if I don’t achieve it and fall slightly short, a final would be fantastic, such a great achievement for me.
“If you don’t aim for it you’re not going to win it. You’ve got to go in with the mentality that you can win a medal.”
That was the mentality which served him so well in the British Championships. Slower on paper than his rivals, he would give everything he had to the race in the final against Sliwinski and Jamieson, and if it was not enough, so be it.
“I stood up behind the blocks, 100 per cent confident really,” he remembers. “I did a personal best on the first length, because I went out as fast as I could go. Then I held on down the second length, tried to hold on so bad. Michael was coming back at me because he’s more of a 200 swimmer, but I just managed to hold him off and qualified for three hundredths of a second.
“I think I swam it really well. Daniel always goes out really fast, and Michael is known for coming back really fast, so I thought I’d have to go out in between the two on the first 50. I just thought I’d try and hold on on the second 50, try and stay ahead of Michael and maybe catch Daniel. I didn’t quite manage to catch Daniel, but I did hold off Michael, finished second and just sneaked on to the team.”
That achievement of ‘sneaking’ on to the team came down to just over a minute of swimming in the final, but it was also the culmination of a year’s calculated hard work, which had seen Benson’s personal best for the two lengths come down dramatically. “Last year’s trials for the world championships, which were in March, I was 63 seconds for the 100m breaststroke.
“Then I went on to the European junior championships and took it down to 62 seconds. Then a couple of months later I went to the world junior championships and took it down to 61.”
That time was good enough to win – and good enough to convince him that winning a place in the Olympics would be tough, but not out of the question. “I realised at that point: ‘I’m only half a second away from the Olympic qualifying time. I think I can do that by the time March comes’.
“Realistically I set the goal, but I knew it was going to be really challenging, really tough, because there are so many top guys in Britain. I thought I would aim for it. It’s unlikely you’ll get there without aiming for it. I just fully focused on making that team. Fortunately I got on, and it’s been absolutely fantastic.”
The obvious question now is, having made the team, how much more can he improve between now and July? “I really don’t know,” he says. “I think there is a lot of time to be taken off my starts and turns, and I am really working on it and I think I’m coming along really well with them.
“I was half a second behind Daniel to the first 15m, so that’s basically just the start. If I could take half a second off there, and another half second at the turn, that’s a whole second just there ... I don’t know if I’ll be able to get to the same level he’s at, but that’s definitely an area where a lot of time can be taken off. And general training should hopefully help my swim speed as well.
“There are a lot of areas to improve. I’m still young compared to the other athletes.”
In terms of being a serious, dedicated swimmer, Benson is just three years into his career. By the time he broke the British record he was well aware of his ability, but after that his progress stalled a bit, until he was faced with a choice: relax, accept that you are a talented swimmer and leave it at that, or devote everything you’ve got to making the most of your ability.
“When I was younger I found it difficult to motivate myself to train,” explains Benson. “I really just enjoyed the racing side of the sport, and was racing really well without putting in too much work in the pool.
“After breaking the British record I kept progressing up until the age of 15. Then my results started to peak a little bit, and I realised you could only progress with hard work in training.
“It was then that I totally changed my attitude towards training. Since then, every day I get in and work my absolute hardest. I don’t know anyone who would put in more effort than I do now. I’m fully committed to it.
“Ever since then I’ve been progressing at such a fast rate, specially in the last 12 months. I’ve taken three seconds off my best time in 12 months, which is almost unheard of at that level.”
A year ago, Benson himself was almost unheard of by the men who inhabit the rarefied level at which he now competes – men such as Japan’s Kosuke Kitajima, the winner of the 100m and 200m breaststroke at both of the last Olympics and who, at 29, remains the best in the world by some distance.
“It’s quite strange, really, because it’s all happened so fast,” the Scot adds. “A year ago I would have just seen myself racing people my age. It’s weird. Kitajima has been my hero and has dominated breaststroke for so long, and to think I’ll be racing him... It’s very strange – but it’s great.”
• Craig Benson is supported by SportScotland Institute of Sport and is a client of Red Sky Management.