Although there are, of course, a number of reasons for honestly giving one's age on various occasions - renewal of documents, medical reasons being just a couple, I can say that I do not give a great deal of thought to age - I am who I am, at whatever age.
It does appear to be fact that there is age discrimination in the job market, as my OH has not worked more than part-time since he was made redundant at age 50, but even that is not always the case. I myself have worked as a freelancer for 20+ years and due to the fact that I work exclusively via the internet these days, most of my clients neither know nor care how old I am as long as I deliver a good job, on time.
I hope and believe that this is the future, where we will be judged on our skill and knowledge rather than by how many wrinkles and how much grey hair we have.