I taught a Freshman Political Science class as part of my Senior Seminar.
My students were uneasy at first because they expected an old frumpy professor, and instead they got a 22 year old. It was the first time teaching anything and I really didn't know what the hell I was doing most of the time, but after a few weeks, the "kids" warmed up to me. I didn't want them to think that I was a pushover or that I was "easy", so I was really hard on them when it came time for evaluations. When I was evaluated by them at the end of the semester, I was told that I was fair.
Apparently I was good enough to teach another course the following semester.