I think as you get older (i'm 48) the consequences of bad decisions become more and more damaging. Just thinking about careers, a major change in career at 27 isn't as consequential as a career change at 50 because you have time to try again. Make a career change mistake at 50 and there isn't much time to right the ship and get back to at least where you were.

My wife and I were talking about making considerable life changes (career and living) in about 6 years as both my boys will be through HS then and out of the house. So these changes, whatever shape they take, will happen in my mid-50s. That's 10 years from my planned retirement (I'm in the US). Any mistake made in those decisions has dire consequences to the rest of my life (and my wife's life for that matter).

As for dealing with imperfections, I've told my therapist "i am who i'm going to be. If that's not good enough for you or society then you all are just going to have to deal with it."