For reference, I went from 60 to meeting my mentor requirements in just 3 days of work. Work I was doing anyway to start on my endgame. (8/8 M3, 3/9 folklore, 1 week of red capped)
But it seems ok. The requirement of reaching 60 is doing the brunt of the work. Going from 0-60 on all 11 took me a bit under 4 months. I know the requirement is just 1 of each, but my first piece of advice as an (almost) official mentor is: don't do just 1 of each. Do them all at once. The real focus of the mentor requirement is the 60s.
You can guide someone pretty well up to 50 and how to start heavensward with just that. The other achievements seem tacked on. It's just a "must have begun endgame," which only requires a very rough understanding (I see some pretty bad collectible rotations from people next to me while gathering scrips). Hell, I had reached the achievements before even attempting to farm aethersands.