In reply to Postmanpat:
> It's very odd. We don't say a baby is one day ld the moment it is born do we?
And therein lies the difference between counting age and time.
It still amuses me to come across millennium plaques which were placed on 01/01/2000.
The 2nd millennium started on 01/01/2001, but we all agreed to ignore that fact in favour of going with the (obvious?) change of year number.