Keats felt from the very beginning an urge to be great. Throughout his career, he was always looking forward to his next project. Though he was very young, he showed the talent of a much more experienced poet. In "On First Looking into Chapman's Homer," Keats discovers and praises the high power of the call of poetry. The poem reads like an origin story for a superhero, for cryin' out loud. He is inspired and wants to prove himself worthy of this great calling.
Bawk bawk! (Sorry, that's our chicken sound. What? It could be worse.) Keats is scared that he won't be good enough. His writing shows how intimidated he is by the great poetry that's already been written.
Keats believes in the power of poetry and desires to follow that path because of the impact it had on his own life.