I'm 35 and overall am feeling at the top of my game. I don't envy the 20 years olds or feel lost. I've learned so much, not just technically but around user and enterprise needs, inter-personal skills, and about myself since I was 18-20 that I absolutely feel better suited for success. I've started eating right and working out, which has helped both body and mind, and I've developed task and time management technique…
> my mind might not be 100% as quick as it was when i was 20 care to elaborate? I'm 34 and I keep hearing that my mind is supposed to slow down but it hasn't yet. I drink 2 cups of coffee a day, don't smoke cigs, am not overweight, try to go for a walk for 30 minutes minimum each day, go to sleep by 9ish and am up by 3 or 4am. I also watch very little TV, read regularly and push myself to learn new stuff on a near co…
http://www.massey.ac.nz/~rmclachl/overthehill.html
However, I don't think it's slowing me down, I'm still capable of learning and producing, and I've learned lots of stuff to "work smarter". I do believe I'm doing myself a disservice by not keeping in shape, and that might be part of my perception of having less energy (but not less enthusiasm).