That one works flawlessly.

DECLARE @DateOfBirth VARCHAR(10)

SET @DateOfBirth = '1960-03-07'

print YEAR(GETDATE()) - YEAR(@DateOfBirth) - CASE WHEN MONTH(GETDATE())*31 + DAY(GETDATE()) >= MONTH(@DateOfBirth)*31 + DAY(@DateOfBirth) THEN 0 ELSE 1 END