At what age would you say you were smartest, if you have noticed any fluctuation? I hear you mental power peaks at about 22 and begins to decline after 26, but that's pretty depressing, and I don't want to believe it, so if you have experience to counter or confirm this, please share. If you have noticed any decline in "fluid intelligence," is it negligible? Does your wisdom and experience outweigh any mental decline…
Software is mathematical but it also requires a lot of judgement and experience. Consider that Guido van Rossum didn't even START working on Python (most popular language on HN) until age 35.
From what I can see 30's and 40's is a sweet spot for a lot of programmers. It seems like a lot of startup founders are young, but I think a lot of the guys actually making systems work have been around the block a few more times.