"One week, one season, one year or two, every shot will seem simple and every putt will look like a tap-in. Then, a week or two later, maybe longer, the shots that used to land exactly where they should will fall just a fraction to the left or right. The putts that seemed to find the centre of the hole will veer off by mere centimetres."
However, she paired the warning with encouragement that golf was simply a sport that offered up more than its fair share of roller-coasters in form and she should have faith in the hard work she had put in to her game.
"Don't panic. The game hasn't abandoned you. You haven't forgotten how to play.
"There is good news. Just as quickly as the game can slip away, with hard work and self-belief it can come back. And when it does, you will be stronger and wiser for having traveled the rough road to get there."
Ko also seemed to reference her rocky history with former coach David Leadbetter, who last year accused Ko's parents of "unbelievable ignorance" in the way they interact with her career.
"Others will criticise you and will question those around you, assuming you are being manipulated or led. Those criticisms and accusations will wound you – knives thrown at those close to you always cut deeper than those you field yourself – but they also make you stronger and more appreciative of the people who stand by your side.
"Your golf swing may come and go, but your family and friends, the people who care about you, will love you no matter what you shoot. Trophies are symbols of what you've accomplished in the past. Your family and friends represent who and what you can be in the future. Their hugs, their presence, their laughter is life's greatest victory."
Ko had one final message for her teenage self and that was to keep things simple, embrace her own personality and let that guide her above any expectations that come with being a professional athlete.
"Be yourself, first and always. If you do that, words like 'brand'' and 'image;' 'platform' and 'presence,' will take care of themselves.
"Be you. And be happy. Do that, and everything else is going to be fine."
Read the full transcript of Ko's letter here.