Spieth dropped out of the University of Texas after his first year, turning professional in December 2012 without having playing rights on any major tour.
Less than two-and-a-half years later, the 21-year-old was slipping on the green jacket at the Alister MacKenzie-designed Augusta National, while his former colleagues were competing at another MacKenzie course in Pasatiempo, California.
“Michael (Greller, his caddie) and I were joking on the first tee,” Spieth recalled. “He said, ‘Aren’t you glad you are not at Pasatiempo right now? Face it, aren’t you glad you’re here instead of there?’
“That kind of sums it up. To have left school and took a chance, and everything that happened in 2013, to have the opportunity to win the Masters last year, which then allowed me to win this year. It’s all run together. It all happened quickly. Sometimes it feels like a long time ago and sometimes it feels like yesterday.”
Spieth, who is the only player apart from Tiger Woods to have won the US junior amateur title more than once, enjoyed instant success after turning professional, finishing seventh, fourth and second in his first three events on the second-tier Web.com Tour.
He then finished seventh in the Tampa Bay Championship before winning the John Deere Classic two weeks before his 20th birthday, thereby becoming the first teenage winner on the PGA Tour since 1931.
His first appearance in the Masters saw him threaten to become the youngest-ever champion when he led by two shots after seven holes of the final round before finishing second behind Bubba Watson, while he remained unbeaten alongside Patrick Reed in the Ryder Cup at Gleneagles before losing a three-hole lead with nine to play to Graeme McDowell in the singles.
Having come into the Masters on the back of finishing first, second and second in his previous three events, Spieth was one of the favourites at Augusta and duly delivered, becoming the first player ever to reach 19-under-par and only a bogey on the 18th prevented him from adding the outright 72-hole scoring record to the 36 and 54-hole records he set on Friday and Saturday.
“It was the ultimate goal in my golfing life when I was a kid,” added Spieth. “I did not expect to get it done at 21. It’s time to get excited about following Bubba as a two-time champion.
“But the ultimate goal that I have mentioned I think each week is try to become the No 1 player in the world. I’m still behind so I’m still chasing that goal. It’s going to be very difficult, but to be a step closer is huge.”
Spieth’s win took him to second in the world rankings behind Rory McIlroy and much has been made about a possible rivalry between the pair.
“As far as (a rivalry) with Rory, he’s got four majors. That’s something I can still only dream about,” said Spieth.
“I’ll never hit it as far as he does and I have to make up for that somewhere else. He’s an unbelievably nice guy, carries that world No 1 with class.
“I don’t know as far as a rivalry right now. I look forward to getting in the heat of the moment with him a couple times in the near future and see if we can battle it out and test our games.”
Next up in terms of major championships will be the US Open at Chambers Bay, where Spieth could have a crucial advantage over the vast majority of his rivals.
His caddie Greller, who was a sixth grade teacher for 10 years before giving it up to caddie for Spieth, lives close to the course and caddied there during the 2010 US Amateur championship, where Spieth shot 72, 83 and failed to qualify for the matchplay stage.
And then comes the Open Championship at St Andrews, a course Spieth played before the 2011 Walker Cup at Royal Aberdeen.
“To go to the home of golf and what I consider one of the coolest places in the world is going to be really special as the Masters champion, with maybe the most knowledgeable fans in the world,” said Spieth.