The Question and Answer section for Don Quixote Book I is a great resource to ask questions, find answers, and discuss the novel.
This is a pretty complex question for this short-answer forum. Check this out:
There is an older gentleman (named Quixana or perhaps Quesada) and he lives in a Spanish village called La Mancha. As the story begins, this man has lost his wits. "His imagination was full of all that he read in his books"stories of medieval...
I do not think his exact age is mentioned other than he was middle aged.