Bonta's poem seems to look back at the moment of birth, though it never says so outright. The "din at my beginning" suggests a loud, chaotic arrival, and the "little head out" is a startlingly physical image: a newborn pushing into the world. The strange phrase "to eat joy" makes that arrival hungry and eager, as if the first thing a person does is reach for happiness.
The second stanza shifts from the body to the rest of the self. The speaker "must leave the remainder of me" behind, to "hear and believe / in the attempt." That reads to me as a kind of trust: the head has gone ahead, and everything else has to follow without any guarantee it will work. The mood is tense but hopeful. The poem is noisy and a little frightening, yet what it values in the end is the willingness to try. Being born, it hints, is the first act of faith, and perhaps every later beginning is too.