I am creating a form using Excel 2010, the individuals using this form will be required to input their date of birth.
I used the following formula to calculate their age -


=IF(MONTH(TODAY())>MONTH(C13),YEAR(TODAY())-YEAR(C13),
IF(AND(MONTH(TODAY())=MONTH(C13),DAY(TODAY())>=DAY(C13)),
YEAR(TODAY())-YEAR(C13),(YEAR(TODAY())-YEAR(C13))-1))

This formula has worked perfectly, however the default age is 113 and is displayed within the cell when the date of birth has not been entered.
My question is that, is there a way to make the default age not visible when the date of birth is not entered? If so, how?