This question has been asked many times and, unless our membership profile has suddenly changed on this site, I know that the majority of people here seem to be over 60. (I have absolutely no idea why that is though. We welcome, and indeed need, younger members!). I'm 68.
I was 70 in March. At the moment I feel 90 due to a pulled muscle, I remember(most of the time) what I've gone upstairs for, do reasonably well at tv quizzes (except Only Connect and University Challenge) and I don't have to carry spare knickers!