As long as you're mentally and physically fit you can do it at any age. But I think the statistic skews way too low today because a lot of the existing popular

As long as you're mentally and physically fit you can do it at any age. But I think the statistic skews way too low today because a lot of the existing popular languages are low hanging fruits. Eich I think said once that he wrote Javascript in ten days, and I don't think you're going to make a popular language in two weeks any more. The standards and expectations on a language ecosystem are so much higher now if you want to add value I'd honestly even say no new popular language is going to be built by a single person. Unless the Lisan Al Gaib of programming comes along and invents an entirely new paradigm.