This is an unmissable achievement...at least as long as you don't get sidetracked for too long and do the main story every now and again.
This is accomplished by completing the 5th main quest of the game, mild spoilers below for more details.
*** Spoiler - click to reveal ***This is the quest that takes you up the 7000 steps to High Hrothgar. After doing some tutorials on your dragonborn shouts with the Greybeards the achievement should pop.