The speaker is a child addressing a mother who gets their birthday wrong, twice. First she posts a staged, photoshopped celebration on Instagram, collecting praise as the "best mom," while the speaker sees through the fake happiness in everyone's "cold eyes." Then, during a supervised visit, she wishes the speaker a happy birthday on April 4th, which is also the wrong day. The poem suggests the family has been separated, since she can only see the speaker with a supervisor in the room.
The mood is quiet, bitter, and sad. The speaker sounds calm, even casual, saying "It's alright. Mothers forget birthdays," but that calm reads as hurt held in check. The closing lines shrink into short fragments: favorite colors, names, the favorite cake. They show that the mistake is not really about a date. It is about a parent who doesn't know her child, and who cares more about how things look online than about who is actually there.