my wife told my daughter about santa til she was about 5.
i then said u have to be careful telling her stories that sound too far fetched, cause one day some weirdo might tell the daughter some other far fetched story for the wrong reason, and she might believe him.
So now, at 8 yrs old, i tell her if some guy who looks unusual asks you to sit on his knee, feel free to punch him repeatedly and call out for dad ! lol
If my other daughter, who is 16 going on 30, saw a santa coming down the chimmney, she would probably tie him up and keep him captive until she got a new car out of him. No car, no leavin the house. lol yes, i have taught them to be shy ! maybe not. lol