Says Stewart Binns who became an author of fiction at the age 50 - he has written the historical novel "Conquest" - in an interview with Helen Lewis Hasteley published in newstatesman.com:
I came to fiction slowly, having worked in television most of my life. Coming from a visual medium, words weren't a major part of my training, but I realised how powerful they could be. I started writing non-fiction connected with the television series I made, and that got me scribbling. Through that process, I thought: I really do like words. By that point I was almost 50, and I thought: could I do some fiction?
So all is not lost. There is still hope for those in their fifties. Hm. Vindicates my belief that one can be a published author at any age.