What are the strengths of “Girl” being written in the second person? In other words, what was the story able to accomplish specifically because it was told in the second person? Then, describe a weakness that the second person created, and describe why you see it as weak.

The choice of the second person as a narrative voice is an unusual one which is always deliberate. Second person gives a text a very particular feel: the reader is necessarily the person being addressed by the text. In the case of "Girl," the effect of this is that the reader is now the recipient of the barrage of information and instruction that is delivered to the girl in question on a moment by moment basis. As the recipient of all this instruction, we can clearly sense how inexorable it feels: the long sentences, broken by semi-colons, add to this sense of continuous instruction and command without pause. The story is exhausting to read; we can only imagine, then, how exhausting this life must be for the girl herself to lead.
There are, of course, weaknesses and downsides to this type of narrative. The chief among these is that we have no idea how the girl feels about all this, other than what we can assume based on our own feelings. However, this may also be seen as a positive thing—we are forced to place ourselves in the girl's position and feel with a true immediacy, rather than being told how this feels. We understand the girl's life directly, rather than at a remove.

Writing "Girl" in the second-person point of view places the reader in the position of the "girl" who is evidently being educated about many different aspects of life. When she is accused of something, like singing benna on Sundays or in Sunday school, we feel her defensiveness. We also sense more easily how the "girl" really does not seem to get an opportunity to get a word in edgewise. We feel her relative powerlessness because we read the text as if it were directed at us—instead of at someone else in front of us.
One potential weakness of writing the story from this point of view is that imperative sentences end up dominating the story. We don't get much description or any background information (called exposition). This really just reads like a list of things the "girl" is expected to memorize and know, going forward. We don't know much about what she thinks or feels at all, and this could be considered a weakness.