Over 40, so far the body hasn't been a limitation outside of the many surgery recoveries (ankle/hip/shoulder).
All that said, I moved to the east coast about 15 years ago so the forecast or lack there of is the biggest problem. We have our days, but there's barely enough surf through the summer to get ready for the good days. I got a 6',10" midlength last year for the smallest days but 90% of the time I'm on my 5'4" groveler or 6'4" step.
Adding mountain biking to my life has been huge for dry-spells, both mentally and physically