The story of wedding in Cana is a gold mine for an allegorist.
“On the third day” (2.1) is a metaphor of “in a short time.” It is employed here to mark the beginning of a new story, but it is pregnant with echo of resurrection of Jesus.
From water to wine: water is a symbol of baptism, and wine is a sign of the blood of Christ, which was poured out for humanity and celebrated during the Eucharist. John later made the connection between water and blood/wine when he wrote, “For there are three that testify: the Spirit, the water and the blood; and the three are in agreement.” (1 Joh 5.8) There are three signs which testify Christ: the Spirit, the invisible sign, who testifies in our heart, and the water and the blood — the visible signs of baptism and Eucharist, which also testify Christ when we celebrate them.
The first of the signs of glory: If you believed that John structured his Gospel such that Jesus did seven signs throughout his Gospel (the second one is when Jesus healed the son of an official in John 4.46-54, see 4.54), the wedding in Cana marks the first instance of such signs. Now, the last sign is supposed to be the crucifixion itself, whereby the readers then must understand that “glory” is interpreted Christologically. Similarly, the abundance of wine and the joy of guests in this story, too, must be interpreted according to this cruciform line. There is joy in glory, yes, but sometimes (?) it comes in the form of suffering.
And there was Mary. If you need to ask Jesus for help, you can always ask Mary, for she will help you in petitioning on your behalf to Jesus!