I am not a school owner, but I'll give you my thoughts.
I am a first degree black belt in Tracy kenpo. My certificate states that I am authorized to teach and award rank. It does not state any special conditions, such as only promote people up to one or two ranks below me, none of that. I am not a member of Tracys organization. My teachers were independent, we did things our own way and we don't care what others think. I have never earned further rank in kenpo, having not had a school to train with once I left high school, moved away to college and got on with my life. But I still practice on my own. In the last couple of years I have also dug into the art and made some changes that I felt were necessary. I kept my instructor informed of what I was doing, got his thoughts and his blessing, and did some rearranging and streamlining. I didn't start to do this until I had been practicing the art for about 20 years.
That being said, I earned my rank at a young age: 16. I knew at the time that I was not ready to start a school (obviously there would be problems opening a business at that age and whatnot anyway), and it has taken me a long time to begin to feel like maybe I have enough experience to be able to offer something of quality. I am 35 now, and I have just started to feel like maybe I could be an effective teacher within the last few years. I still do not teach, but I have had various people ask if I do. I just don't have the time to commit to it right now, otherwise I might.
In the meantime, I have studied various other arts with other teachers. I studied Capoeira for several years, (left for a few years but recently returned) and reached the rank of Graduated Student, signified by wearing a blue belt (we have a very different belt system in capoeira, no black belt, only colors). Blue belt in our system of capoeira is probably roughly equivalent to first degree black belt in an Asian system, but within the proper context of the art, of course.
I have spent a few years training in Wing Chun. My teacher verbally told me that if I ever decide to teach, I was welcome to teach the Wing Chun as well. He felt that what I have learned from him belongs to me and I am welcome to do with it what I will. He never gave me a certificate, just word of mouth. I have certainly not mastered wing chun, and don't know everything about it, but he felt that the things I have learned, he was satisfied that I could do a good job of passing them on.
I have spent about 8 years training with another teacher (still with him) who teaches several arts, my focus being in Tibetan White Crane kung fu, and Tai Chi. Under him, I am a green belt, but our ranking system is very loose and not given much attention. He has not given me permission to teach.
I guess what I am trying to say is, don't be in a hurry. Sometimes earning rank doesn't mean you are ready to be teaching, at least not on your own. Take your time and get some experience under your belt. Teach under your instructor if you can, keep training, explore other arts, do whatever you can to solidify your background. I know that if I had tried to open a school as soon as I was legally able to, after earning my black belt, it would have been a total failure. I was simply not ready, and not mature enough to handle such a thing. Now, almost 20 years later, with a lot more experience in life and the martial arts, I finally think that maybe I have something to offer. If circumstances allowed, I would be willing to take a small number of dedicated students. I am not interested in running a commercial school. I would rather just meet at my home, or in a park with 2 or 3 people and train together. That sounds like a good start.
Hope this helps to give you some perspective.
