Sterling's nickname is "Preacher" because he's open about his faith, which makes him a bit of a standout. Sterling's not embarrassed to be a Christian even if it means that other people think he's a bit odd.
It's always something with these guys. Either they're trying to draw me into an infantile game of The Dozens so we can trade insults left and right, or they're slapping porno pictures inside my locker hoping to set me off. If they had some direction in their lives like Raul, Devon, or Raynard, they wouldn't have time to worry about me one way or the other […]
As if any of that could stop me from believing in God. (44.17-18)
Other kids at school might think Sterling is perfect or a little goody two-shoes, but inside he knows he's not. He gets angry, too, and he works hard at being forgiving and to keep himself on the straight and narrow.
So no, Sterling isn't perfect. But he does have confidence—he knows he's destined for great things. He's going to college; he's going to be a teacher; and he's never going to stop believing, no matter what anyone says. The guys from Journey would be proud.