Repetition calls attention to important images and ideas in the poem. For example, lines 1 and 6 feature anaphora: both begin with the phrase "I can remember you." This repetition firmly grounds the first stanza in the speaker's past. Later, readers will learn that the speaker is looking back on this scene from the present, as her now older daughter stands before her; the phrase "I can remember you" collapses the space between the present and past, reflecting that, to the speaker, her daughter will always be her baby.
At the same time, and somewhat paradoxically, the repetition of this phrase hammers home the speaker's sense of her child as a separate person. Note how she doesn't say, "I can remember giving birth to you." Instead, the speaker immediately talks about her daughter as though she were an independent being before she's even physically separated from the speaker's body. The speaker doesn't just remember going through labor, she remembers her child herself.
Lines 16-17 contain both anaphora and more general parallelism:
[...] We want, we shouted,
To be two, to be ourselves.
Repetition makes the language more intense, in turn evoking the intense emotions of the speaker and the child both as they get ready to "confront" each other for the first time. This phrase sounds a bit like a tongue twister, which is intentional: the words seem to bleed together, evoking the ties that bind mother to daughter even as they want to be separate. (Note how "two" is a homonym of "to," making the language sound even more twisty and repetitive!) Both "we" and "to be"—words related to existence—appear twice. The use of repetition reflects the fact that there are two unique people here—two "we"s" and two "to be"s—while, ironically, reflecting how in sync mother and child are even as they are straining to "become separate."