Till about 2 generations ago, few, if any, knew their age or the year of their birth. Large parts of the country still remember their birth as "It was some 3-4 days after the Poornima, in the season of spring." or "i was born the year we had the drought. My mother says there was no water for us." or simply, "Some year, at night. It was summers, my mother tells me."
I've been thinking of this - the lack of need to remember a birthday, a date and the year. What an awesome luxury!! You are old if you do not have your teeth any more. You are an adult if you start to do *ahem* adult things, and you are a child if you do not do hard labor in the fields. Simply put, when we remove that number, we remember our life by its REAL milestones - that I am a grandmother now, that my teeth have come, that i have started to lose hair, that it is now difficult to put hard labor in the fields.. the things that really matter.
When you do that, you can not hide behind a number to explain why you have cholesterol, why you cannot have any more children etc. Some months ago, there was this news item of a man who fathered a child at the reported age of 90. The mother of the child was then 45. How did she give birth to another child, in the middle of a village, at the age of 45? Simple, she had no idea that women are not supposed to give birth at 45. What's more, she did not know she was 45 and should be looking at menopause, not childbirth.
Having a number and a day next to our existence on earth is of great value. It helps us measure (and get a birth certificate). But doing away with that number has its advantages too.