Remember all the stuff we forgot, or got wrong when we were 3o years old? Yep, me too. Hmmm...'taint no perfect people running around last time I checked. The best of the best of us forget stuff, and not just occasionally. So, old age be damned! (Why do you think bright college whiz-kids take such prodigious notes? Because they would forget even the most important things.) Heck, even Einstein littered his office with reams and reams of notes. I am willing to bet that most of us here are going on bare brain matter, rather than notes. So yeah, of course we make mistakes. We can expect to have to backtrack and make corrections; after all, we're human. Mistakes come with the territory of being human, not just old age.
And there are benefits to forgetfulness, too: I can enjoy the same books and movies over and over again because after a few years, I sometimes forget the endings. So, there, 'taint all bad.