That happened a month later and Ko's transition to the professional ranks was an immediate success. She took her first title the LPGA Swinging Skirts in Taiwan in only her second start, since winning two more times in her rookie season on the LPGA Tour.
Ko has recently had two weeks away from golf after the Canadian Open - one of the longest breaks of her young career - and it was just what she needed.
"I pretty much chilled out at home," she said. "I just tried to be a normal teenager - had some fatty food. That's not what the normal athlete would be. But I just enjoyed not touching my clubs and not having to worry about what else was going on.
"During that whole time I really did nothing. I probably gained some weight, too, but to have a week off during the season, that's not what I would have planned, but I think it was a good time for me."
It was also good for her ailing wrist. Ko has had to manage the pain in recent time but she said the injury is feeling a lot better.
"I haven't been worrying about it, which is really good because the game itself is pretty tough and there are other things I need to worry about. My wrist is feeling good and I think I'm feeling good. So hopefully I'm prepared for what's coming."
Ko said the challenge at the Evian Resort Golf Club is different to what she remembers, as the course has more run and many of the tee positions have been pushed forward.
"But I think the course is great. There are definitely tough holes out there, but at the same time there are some opportunities for us to make some birdies."
Ko will tee off at 6:40pm (NZT) alongside defending champion Suzann Pettersen of Norway and American Lexi Thompson.