It seems like you've accomplished a lot. I know everyone fails, at least occasionally. Tell me about something you failed at.
A When I was a freshman in college I decided to run for president of the management club. My opponent was in his junior year. I came up with what I thought and still think was a great platform. I campaigned vigorously. Unfortunately I lost the election. I'm pretty sure it was due to my lack of experience. I ran too early in my school career. Two years later I ran again and I won.