Yes and no.Asking for a sign certainly is asking a bit about or like , “what ,thru me…are you sure you want me because of such and such a thing”( poor speaker or not brave…or knowing no man?) . It is a bit of a “how” question.
As to sign and Mary, the sign is just that, how a virgin, who knows no man, can conceive and bear a child.
"Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.”
Again, don’t think Mary asked for a sign, but how It would be implemented, without a man. A straightforward, humble question from a young but willing adolescent.