Get accurate age by date

DECLARE @Age int
DECLARE @Date_of_birth datetime
DECLARE @Today varchar(11)
SELECT @Date_of_birth = '03/05/1979'
SELECT @Today = GETDATE()
SELECT @Age = FLOOR(DATEDIFF(day, @Date_of_birth, @Today) / 365.25)
PRINT 'Your age is: ' +  CONVERT(varchar, @Age)