I don't mind aging as long as I have good health. I'm more relaxed about life, have a larger perspective based on experience of the world around me and no longer "must" do things for career, job or livelihood. Instead, I have the luxury of choosing how to spend my time, which is all the more valuable to me as I recognize the simple fact of mortality.
I do occasionally forget things I once knew but unless it starts to interfere with my day to day life, I'm tolerant of it. I've probably mentioned Conan Doyle's description of Watson's bafflement over the things his friend Holmes knew and didn't know-- in a "Study in Scarlet." Holmes described the mind like an attic--with only so much storage space for immediate access.
I'm also struck by the amount of change in the world and culture in the last 20 years. I don't want to provoke a political discussion here but remember the impact of Tofler's Future Shock and comparisons to the beginning of the 20th century, which was a period of rapid technological and cultural change. I think we are undergoing a similar shift in the world around us, which I find fascinating in some ways. Yeah, my popular culture references are now dated- many of the younger people at the gym, for example, never saw Apocalypse Now, or even Airplane, so riffing lines from those movies makes me seem a little odd. Then again, I've always been a little odd, and that never bothered me either.