Our son was just past 3. I remember because he used to drive his preschool teachers nuts. They'd try to fudge the time to get the kids going in one direction of the other and he'd pipe up with the correct time. One teacher used him to her advantage, though -- she made him the classroom clock monitor. She created the job just for him and said it worked great! He was in charge of giving 5 minute warnings for lunches, recesses, etc.

Being offended is a natural consequence of leaving the house. - Fran Lebowitz