Age Calculation
You can use DATEDIF as in =DATEDIF(A1,TODAY(),"y") or =DATEDIF(A1,NOW(),"y")
An alternative to DATEDIF.
=TEXT(IF(OR(MONTH(TODAY())>MONTH(A1),AND(MONTH(TODAY())=MONTH(A1),DAY(TODAY())>=DAY(A1))),(TODAY()-A1)/365.25,(TODAY()-A1)/365.25-1),"0")