Ordering AA before A

I would add another column "orderid" (INTEGER or even TINYINT) to your table, and order by that column instead.

Assuming A is the only possible repeating letter, you can do this:

SELECT  *
FROM    bra
ORDER BY
        LENGTH(size) DESC, size

But a better solution would be to create a conversion table which would store all possible sizes (European, Japanese etc) including metrical on which yoг can order.

You may use it to build conversion charts and show the sizes in person's preferred system as well.