In "Before You Were Mine," the speaker (who, from context, seems likely to be the poet Carol Ann Duffy herself) bends time and space to address her mother—before she was her mother. This vibrant young woman, the poem suggests, wasn't just a mother-in-waiting, but a lively, colorful, and charming person in her own right.
The first two lines establish that the poem takes place 10 years before the speaker was born. In this moment, the speaker's mother is still a young woman, carefree and full of life. She and her friends stand on a street corner and "shriek" with laughter so hard that they nearly fall over.
Here, the poem doesn't just bend time and space, but also mixes them together. The first line puts the speaker 10 years away from the specific "corner" of the street on which the three girls are laughing, rather than just 10 years away from being born. This idea of the past as a far-off place speaks to the youthful freedom of the moment: to these young girls, the future from which the speaker writes is as distant and strange as a foreign country.
The speaker's mother seems right at home in the world of the past. She's accompanied there by her friends "Maggie McGeeney and Jean Duff." The specificity of these names makes these women seem more real, like people the speaker might have known or heard about while she was growing up. They also set the scene in mid-20th-century Glasgow, where Duffy's mother grew up. And the colloquial word "pals" in line 2 shows that these three are close. The alliteration of "Maggie McGeeney" also has a playfulness that suggests the shared laughter and joy between the three young women.
But those spelled-out names could also be a little melancholy: the mother probably wouldn't have used surnames to describe her "pals" back when they were hanging out on street corners together. The surnames thus make the friends seem realer, but also more distant—like historical figures, or names on a tombstone. This will be a poem about how the past is both living and lost.