Alright. I've been watching this get completely out of hand!
Robin has lots of valid points! What happens if you are starting a kid off on the wrong foot because you yourself haven't had enough lessons or experience teaching or learning how to teach trumpet. People say that you need to be the most experienced and talented to teach high levels of trumpet, but there is also a lot, if not more, talent needed to teach beginners.
Speaking for myself, I only started teaching private lessons to elementary school kids when I was a junior in high school. This was after COUNTLESS HOURS of practice, taking 8 years of private lessons from two different teachers, and finding out I wanted to become a music education major. If you feel you just need the money and that's why you want to teach, you shouldn't. If you feel you are qualified and you have a clue on what your pedagogical approach should be, then go ahead a try teaching. You may not find that teaching is your thing. It is tough, if done right. Just like playing the trumpet it's tough, but the masters make it look easy. People that think then can play a double C like Maynard with half an hour of practice will probably think they can teach like Thibaud after giving two lessons.
P.S.- If you don't know what the word Pedagogy is... you probably shouldn't give lessons, but take lessons.
P.P.S.- If you haven't heard of Pierre Thibaud.... you probably shouldn't give lessons, but practice some of his ideas.
P.P.P.S- My .02 cents