Problem With Converting To Date

SELECT DISTINCT
                      CONVERT(varchar(20), CAST(MONTH(dbo.classgiven.classdate) AS varchar(2)) + '-01-' + CAST(YEAR(dbo.classgiven.classdate) AS varchar(4)), 1) AS ok,
                      dbo.classT.discount
FROM         dbo.classT INNER JOIN
                      dbo.classgiven ON dbo.classT.classcode = dbo.classgiven.classcode
WHERE     (dbo.classT.coned IS NOT NULL) AND (dbo.classT.discount = '-1')

 

why wont ok come out as a date and sort as a date?

i looks like a date but sql server will not sort OK in order. my god please help