Deliberate, open disobedience had never yet occurred to the Kid as a moral possibility.
If your mother or your Daddy Chip told you to come back, you had to come; therefore he did not want to be told to come.

Doctor Dell had told him that he could go on roundup some day--the Kid had decided that this was the day, but that it would be foolish to mention the decision to anyone.

People had a way of disagreeing with one's decisions--especially Doctor Dell, she always said one was too little.

The Kid thought he was getting pretty big, since he could stand on something and put the saddle on Silver his own self, and cinch it and everything; plenty big enough to get out and help the bunch when they needed help.
He did not look so very big as he went trudging down alongside the creek, stumbling now and then in the coarse grass that hid the scattered rocks.

He could not keep his head twisted around to look under Silver's neck and watch the hill trail, and at the same time see where he was putting his feet.