I am not really sure what age I was, probably about the same as many of you. My folks always had a lot of answers for the Santa Questions.
The Mall Santa's were not REALLY Santa but they worked for him and would report back about the kids and their wishes. After all, Santa had a factory to run.
Santa didn't bring you ALL the presents under the tree, mommy and daddy bought some, but he did bring select ones just for you.
Stuff like that. I credit my parents inventiveness and making the fantastic realistic which kept me believing all those years. I retell the same things to my son now.
"I have always thought of Christmas time, when it has come round, as a good time; a kind, forgiving, charitable time; the only time I know of, in the long calendar of the year, when men and women seem by one consent to open their shut-up hearts freely, and to think of people below them as if they really were fellow passengers to the grave, and not another race of creatures bound on other journeys." ~Charles Dickens