'i should've steeped in; fourth grade is no excuse. besides, it doesn't get easier with time, and twelve years later, when vietnam presented him much harder choices, some practice at being brave might've helped". why is this quote important?

Tim remembers when he was a boy and he did not stick up for his friend Linda. At school, Linda wore the strange cap every day. One boy kept threatening to pull it off her. Tim wished he could do something, but he wasn't brave enough. "I should've stepped in; fourth grade is no excuse. Besides, it doesn't get easier with time, and twelve years later, when Vietnam presented much harder choices, some practice at being brave might've helped." Tim sees this lack of bravery extending to his experience in Vienam.