COLUMBUS, Ohio — Edwin Maldonado was 5 years old the first time a teacher asked him what he wanted to be when he grew up. He was a little embarrassed by the answer, he admits now, though he can't quite explain why. "I said, I want to be a jockey," he recalls, laughing softly. "I always wanted to be a jockey." Years later, Maldonado is standing at the threshold of the Kentucky Derby — his first — and his dream is set to play out in front of 100,000 people and millions more watching at home.