as long as you feel you have the time/flexibility/energy/whatever to make it happen, you're not too old. the standard difference is that younger people tend to

as long as you feel you have the time/flexibility/energy/whatever to make it happen, you're not too old. the standard difference is that younger people tend to have more flexibility in failure -- if they don't succeed they can still get a regular job and retire and live happily ever after. they don't have a family, a house, sometimes don't have a car, are comparatively more healthy, etc. its easier to live off of nothing, bootstrap themselves, and fail gracefully. a prototypical older person has more responsibilities, has bills to pay, has a family to support, etc.. there's more of a need of a steady income stream. if you feel like you're in a situation to be able to follow your idea and still uphold your responsibilities, then go for it.