In The Absolutely True Diary of a Part-Time Indian, how does Arnold show traits of determination?

In The Absolutely True Diary of a Part-Time Indian, Arnold shows determination when he insists on transferring to Reardan.

The roots of Arnold's decision to leave starts off at anger at unfairness.  When his geometry teacher passes out textbooks, Arnold is dismayed to find that he is given the book his mother used:  "My school and my tribe are so poor and sad that we have to study from the same dang books our parents studied from. That is absolutely the saddest thing in the world."  Arnold voices his displeasure as he throws the book at his teacher's face.  Arnold speaks out against a system that would have him use books that his parents used.

Arnold moves his anger to a more constructive level in his determination to leave Reardan.  After his talk with Mr. P, Arnold realizes he might be destined for something better than the world of the reservation.  Arnold knows if he stays on "the rez," he will succumb to the world of broken dreams and dispelled hopes that have afflicted so many Native Americans.  Arnold is determined to not let this happen.  He directly tells his parents what he wants:  "I want to go to Reardan,' I said again. I couldn't believe I was saying it. For me, it seemed as real as saying, 'I want to fly to the moon."  His determination is underscored when he tells his parents that "[i]f I don't go now, I never will. I have to do it now."  Arnold is determined to leave the reservation in the hopes of something better for his future.