Indeed. We know from Voyager that Tuvok had to give up his attempt at Kolinahr because his ponn farr kicked in. So it seems a Vulcan either achieves Kolinahr within seven years or never.
I'm not entirely sure of that.Suppose as a Vulcan, you have spent 5 years at it, and then Ponn Farr kicks in. You go through that phase, and after that you resume your Kolinahr training/meditation/whatever. Would you have to start at square 1 again, or would at least some of the training / mental discipline you got earlier carry over / be re-established quicker?