Protecting the nation
Even as a young boy, Brooks knew he wanted to serve his nation and that he would enroll. This determination had compelled him to work hard throughout his life in order to assure his acceptance into the army. At this young age, though, all he knew was that he would grow up to be a generational hero. He had no idea that being in this position entailed handling deadly weapons, fighting enemies, and maintaining mental clarity.
He must keep his mental courage at all times. Being separated from family and witnessing the carnage of battle transforms a person. He made the decision at this moment that dating was not for him. If he wanted to make one of his beliefs, he would be punishing his family. He was terrified of the future and what it held until he met the woman of his dreams one day.