Chapter 12 picks up when Mary has finished her portion of the weaving project. She takes the scarlet and the purple to the priest and he blesses her, "O Mary, the Lord has magnified your name, and you shall be blessed in all the generations of the earth."
Mary, happy, heads over to Elizabeth, her kinswoman. Who, as we recall, is the wife of the high priest Zachariah and the mother of St. John the Forerunner. When she arrives, Elizabeth is working on scarlet thread. Presumably *not* for the same project, since Elizabeth was not a virgin. Notice the scarlet of martyrdom and/or sacrifice again?
Here we have a scene that is also presented in Luke, where St. John leaps in his mother's womb at the presence of Christ so near him, within Mary. And Elizabeth proclaims, "Whence is this to me, that the mother of my Lord should come to me? Look how the child in me leaps and blesses you!" So this is six months since the veil project began, because that was about the time when Zachariah was struck dumb for doubting the Lord.
Mary seems to have...almost pushed the fantastical nature of her pregnancy from her mind in this chapter. She knows that something out of the ordinary and important has happened and is continuing to happen, but she doesn't seem to dwell on it. Like she's just trying to live her life normally.
Mary remains with Elizabeth for three months and her pregnancy progresses. She becomes afraid because her pregnancy is becoming impossible to hide, so she goes home and hides in her home from the rest of Israel.
At this point in time she's sixteen years old, so she's been married to Joseph for three years.