Note that Mary is mentioned first, rather than Jesus, and that Jesus and the twelve were “also invited.” Jesus was known as “Master” and Mary was the Master’s mother. As such, an invited guest’s wishes would be respected. In any event, once Mary advised them to listen to her Son, His command or request would have been carried out, since He was a man, rendering the point moot. Yet, there must have been something about Mary, to coin a phrase.
This is a demonstration of Mary’s intercessory ability with her Son, so as to call His favor.
From the Haydock commentary:
Ver. 1. The Mother of Jesus was present. It is supposed she was then a widow, since in all the rest of the history of Jesus, not a single word occurs respecting St. Joseph. (Calmet)
Ver. 3. They have no wine. The blessed virgin Mother was not ignorant of the divine power of her Son, and that the time was come when he designed to make himself known to the world. She could not make her request in more modest terms. (Witham)
Ver. 4. Some of the Fathers have spoken without sufficient precaution on this action of the blessed Virgin; supposing she was actuated by some inclination to vanity, in begging her Son to perform a miracle on this occasion; that some of the glory of it might accrue to her, and that on this account our Saviour answers her with severity, saying, Woman, (not Mother) what is it to thee or me. Other Fathers, with more reason, attribute the interference of the blessed Virgin to her charity and compassion for the new married couple. Whatever turn be given to our Saviour’s answer, it must be acknowledged it has in it the appearance of something severe. But the Fathers have explained it with mildness, observing that our Saviour only meant to say, Mother, what affair is it of ours if they want wine? Ought we to concern ourselves about that? Others think that he wished, by these words, to let his Mother know that she must not forestall the time appointed by the heavenly Father, as if her demand were unseasonable and out of time. But most of the Fathers and best commentators understand, that he speaks here not as man and Son of Mary, but as God; and in that quality, he observes to his Mother, I have nothing in common with you. It is not for you to prescribe when miracles are to be performed, which are not to be expected in compliance with any human respect. I know when my power is to be manifested for the greater glory of God. (Calmet) —See the like forms of speech, Mark i. 24; Luke iv. 34; &c. — My hour is not yet come. It is not yet time. He waited till the wine was quite done, lest any should believe that he had only increased the quantity, or had only mixed water with the wine. He would have his first miracle to be incontestable, and that all the company should be witnesses of it. (St. Augustine, et alii patres passim. — Christ’s first miracle in the New Testament, was a kind of transubstantiation in changing water into wine; the first miracle Moses performed when sent to the Jews, was transubstantiation. (Exodus iv.) The first Moses and Aaron performed, when sent to the Egyptians, was transubstantiation. (Exodus vii.)
There also was some speculation about Simon Kananaios (aka Simon the Zealot), because his name can be interpreted as saying he was from Cana. (Actually, it’s from qana, zealous, so it’s just Simon the Zealot again. But it was a nice try.)