In the broadest sense, she knew when Gabriel announced and she believed. She spent her whole heart loving, serving, and believing her only son. She certainly knew when he answered but perhaps she knew when she thought to ask.
The Book is SILENT on any 'knowing' by Mary.
Rome fills in the blank once again.
That part comes across as non-answer, for we were speaking directly of the miracle at Cana.
There is no reason for us to assume that she at that time knew much of what her son's own ministry was to be about in close & full detail --- as in herself having foreknowledge of events and sufficient insight as towards His truly divine (yet also truly human) nature -- and just what He would eventually show Himself capable doing of -- beyond what is otherwise written of that she was prophesied to herself about Him (her own son).
We know also (for the scriptures tell us) that Jesus Christ Himself could not very well perform miracles among His own clan and kin (Matthew 6:4-5) and as it was also put when speaking of a short period He was again in Nazareth, after having begun His work of ministry; Matthew 13:58
In your reply you had said also;
Whoa. Stop right there. What's this "when she thought to ask" perhaps business? Perhaps?
I doubt that she "knew" what would transpire, yet at the same time can believe that she was prompted into saying what she did -- much as a great many other individuals spoke of what was within themselves -- to which Jesus would then respond, revealing and teaching us much. But if this 'revealing in the scriptures' process includes that she was deliberately trying to coax some miracle out of him -- the likes of which we do not have reasonable grounds to consider she would have known His capability for, wouldn't that sort of thing fall towards realm of tempting even God?
If you be the Son of God -- then turn these stones into bread -- said the Devil.
Would we now have Mary, herself knowing better than anyone that her son was no ordinary mortal, having been conceived within herself by way of the Spirit having overshadowed her (as that is written) wordlessly communicate to her own son "would you please turn basins full of water into wine?" ?
I do think it best for us to not turn her simple observation "they have no wine" into a purposeful request on her own part.
Wouldn't that sort of assumption (that her observation was a form of request -- look! do something!) if not tend towards comparison of Satan tempting Jesus (to perform a miracle) at least make Mary something of a stereotypical guilt-tripping "Jewish mother"?
When otherwise, she was just pointing something out -- which as I explained, was an aspect which was important to Jewish weddings of that era (and interesting enough still carried over to this day in Jewish traditions).
From wider context we can see that the wedding party had had at least *some* wine previously, or else the comparison to what was brought out later being better would not have been made.
As for assuming that she knew when He answered responded to her statement of observation, that ---> something miraculous would take place, as I took pains to explore possibilities for in previous comment, unless we assume (and one simply must keep track of one's assumptions) that there was something revealed to her by the spirit then, of what would soon occur -- as in he would do *something* related to this issue of the supply of wine for the wedding party having been too soon exhausted, what could be much less of assumption would be for her to have then and there "picking up upon" or sensed an impending move of the Spirit (which does come across in the texts in my own reading of them).
I'm wondering at this point...did you read any beyond a sentence or two which I just wrote out to you -- before having responded as you did? I did touch upon this aspect...
What of the rest of what I had just put before you? You know -- like monotheism? Does that ring a bell?
The miracle of the water being turned to wine at the wedding in Cana is more about the significance of marriage, even the espousal of Israel and the Church as Bride and in realm of Spirit (in God's own economy) that either impending or ongoing(?) realization of that heavenly wedding (which shall endure forever) including those "higher" aspects being showcased in the Hebrew tradition of wine being abundant, that all may have their fill and not want for more during that celebratory gathering and ceremony. L'Chaim --- to Life
Those things...things of that sort are what those passages of scripture would indicate to a Jew whom knew his own religious traditions, including what that tradition regarded as scripture --- without a foremost take-away from those passages of John 2 including --- one should pray to "Mary" in order for her to point to Jesus while saying "do whatever he says".