Quote:
my best guess is i really need to get it via datagridview not in database
You're wrong. You should work on data instead of datagridview's cells/rows!
A proper SQL statement to filter data based on year and month is:
SELECT FirstName, MiddleName, LastName
FROM yourTable
WHERE YEAR(DateOfBorn) = @ayear AND MONTH(DateOfBorn) = @amonth