Grace's speaker spends most of "A World Once Starry" insisting she has no regrets, then closes with a plea: "Please, know that I am sorry.." That collision between defiance and apology drives the poem, and everything before it is arranged to make the collision hurt.
The speaker looks back on a past where "everything was bad," where she "gave away my youth" and took on the job of protecting "her." Judging by the pronouns and the phrase "our situation," this is someone younger and dependent, perhaps a sister, though the poem never names the relationship or the danger. We get the emotional outline rather than the facts, which keeps attention on the speaker's inner conflict. The central idea is that protecting someone's innocence can cost the protector her own, and can even turn her into the thing she was guarding against. She "won," but with a telling hedge ("as far as I know"), and along the way grew angry "because she had something I want." What she wants is the very childhood she defended.
The construction is plain and speech-like. The lines are short and the rhythm has no steady metre. The rhyme usually falls on every second line: "bad" with "had," "truth" with "youth," "I" with "cry," "vault" with "fault." Some rhymes are slightly off ("won" and "want," "regrets" and "threat"), and the grammar bends, as in "to protect her and I" and the sudden slide from "had" to "want." These roughnesses make the speaker sound like someone talking straight rather than polishing a performance. That suits a poem about a person who learned early "not to let anyone see me cry."
Its imagery is built on darkness and locks. The speaker is "brought out of the dark," yet later admits she has "brought darkness" herself. The lock image appears twice with opposite functions. First she is trapped: "I had no key to this locked door," as if her anger were a room she couldn't leave. Then she becomes the jailer, locking "any doubt I had in a vault." The second lock fails at once: "But inside I knew, / That none of this was her fault." The "monster I had known before" hints at a cycle, a harm she has seen and now finds herself repeating, though the poem doesn't say who the first monster was.
The middle of the poem tries to argue the guilt away. "Because of me, / She will stand up to every threat. / Because of me, / She will fight." The repetition sounds like a chant, and the confident future tense gives the speaker something to hold. "Over time, / Everything will turn out right" is so flat and tidy that it reads like reassurance she needs for herself. "That must be done" borrows the language of duty, and "while I'm gone" adds a note of farewell. The poem leaves open whether she is leaving or something graver.
Then the structure collapses. The final lines shrink to fragments: "I brought darkness / To a world / Once starry." The title's image arrives only here, and it is the poem's quietest and most devastating one. The stars are the sister's world, the unspoiled sky the speaker fought to keep, and the speaker admits she dimmed it. The doubled full stop after "sorry," whether deliberate or not, leaves the apology trailing off.
What makes the poem worth reading is its refusal of the easy hero story. The speaker really did sacrifice for someone, and she really did resent her for being spared. The poem holds both truths without letting either cancel the other. Her "no regrets" is sincere and her "sorry" is too, and the gap between them is the most honest thing in the poem. It suggests that good intentions don't erase harm, and that the people who shield us may be hurting while they do it.