It's really interesting that as I read your message, reminds a lot of what I was thinking every time I go promote to a new belt. I never felt that I was ready.
To give a example, when I was brown I started to have some good results on local tournaments, I was building my confidence up and out of the blue I got my black belt. I didn't feel ready at all. My first year fighting the WORLDS as black belt I lost in the first round and the champion on the brown belt was a guy who had lost for me a couple months before. At the moment, I felt even worse. But just a year later I won the World as a black belt, beating the champion of the year before...
If you were my student, I would be very happy if I decided to give you the belt and you were feeling like you were not ready yet. Your teacher probabily knows you are ready and the fact that you feel you have to improve more is the ignite to keep growing.
I don't know your game, but I have the feeling you will do just fine. Even if the results are not what you expect at first, dont allow that to put you down. The color belts are just experience for you to become the best black belt you can be. Enjoy the path!