How to calculate accurate age from date of birth in sql

DECLARE @date datetime, @tmpdate datetime, @age int
SELECT @date = '02/25/91'
SELECT @tmpdate = @date
SELECT @age = DATEDIFF(yy, @tmpdate, GETDATE()) - CASE WHEN (MONTH(@date) > MONTH(GETDATE())) OR (MONTH(@date) = MONTH(GETDATE()) AND DAY(@date) > DAY(GETDATE())) THEN 1 ELSE 0 END
SELECT @age