All that we ask is that you have gestated long enough for your embryonic fissure to close. There is no age maximum, and elderly volunteers may indeed come strapped to a board and propped against a wall if need be. I'd like to come, but I fear commitment. You're not obligated to stay, or come every week, or do more than you'd like to do. We just hope you'll find it fun enough that you'll want to.
Most people do.