I generally agree with this, but when he said that Mary was surely terrified, I thought "no she wasn't!" maybe she was, but I think that if she was, she was very much a "feel the fear and do it anyway" kind of person.
Yes, at the Annunciation Gabriel says "Do not be afraid" -- because angels always say "Do not be afraid" -- but Mary ultimately agrees to God's wacky plan. [Luke 1:26-38]
And then, while pregnant, Mary travels some 90 miles [cite] (unclear whether she traveled with anyone else) to visit her elderly sister Elizabeth (who is also miraculously pregnant, and has been for six months). And when Elizabeth recognizes not only that Mary is pregnant but that she is pregnant with Divinity -- which we don't have any indication Mary had told Elizabeth about before arriving (she seems to have gone pretty immediately) -- Mary's response is a hymn of praise about how God is going to turn the world upside down. [Luke 1:39-55]
Black gay Episcopalian Broderick Greer suggests that the Magnificat is a protest hymn that Mary goes on to sing to her child (that Jesus learned a lot of what formed his life and ministry from his radical mom).
And then when Elizabeth gives birth, Mary (having just finished her first trimester) goes back home [Luke 1:56-57] -- only to have to travel another 80 miles or so for some plot device census probably six months later when she's about to give birth any day now [Luke 2:1-6]. Now, if I were going to pick some item from Luke's "Christmas" narrative to suggest that Mary was afraid, this would be it. Because the idea of government wanting to know exactly who all lived under its control and where they lived feels very present.
And Mary ends up placing her baby in a manger (an animal feed trough) because there was no room for them at the inn [Luke 2:7], and in case that wasn't enough dirt and animal, a bunch of shepherds show up, having been sent by angels [Luke 2:8-20]. And we read that, "When they [the shepherds] saw this [Mary and Joseph, and the child lying in the manger], they made known what had been told them about this child; and all who heard it were amazed at what the shepherds told them." [Luke 2:17-18] -- so maybe Mary and Joseph weren't as alone as the story indicates (for example, last year's "Jesus was not born in a stable" -- which I thought surely I had read longer ago than last Advent) 'cause who is this "all" that the shepherds report out to? 'cause they haven't even returned to where they come from yet -- "But Mary treasured all these words and pondered them in her heart." [Luke 2:19] So whatever weirdness was happening, Mary rolled with it all.
In "O Little Town of Bethlehem," we sing "be born in us today" to the Christ child, but I wonder if there's value in seeking to have something of Mary born in us.