What happened in Book I to change Ántonia’s mind about Jimmy being a little boy? Why was she so impressed with what he did?

Ántonia screams in Bohemian and points at a huge, coiling snake as big as Jim's leg. Jim rushes up to it and digs into its neck with the spade, while it coils furiously around his feet.

After he kills it, Jim feels sick and is irritable. Ántonia comforts him and tells him how brave he is. They look at the snake, who is five and a half feet long and twenty-four years old. Jim drags the snake behind him on the way home and feels proud of having killed it. Otto Fuchs tells Jim that he is lucky to have killed the snake so easily, and Ántonia tells how brave Jim was. Afterwards, Jim realizes how lucky he was to have had a weapon available and how lazy and old the snake probably was at the time. Nevertheless, Ántonia treats him with more respect from then on.