Basically, I knew that I wanted to serve in the US military. The only question for me was how, when, and where. So, with that intention already set for myself, I decided that I would rather fulfill it in the best way possible rather than just getting by. I was also sure that I wanted to go to college before too long.
When I was a sophomore (I think) I read about West Point being named the number one college in the nation by Forbes, which caught my interest. After looking into it a bit more, I realized West Point met both of my goals - for the "exceptional" aspect of the Army as well as for my education. Add onto that the enormous prestige and history of the Academy, and I was totally sold on West Point.