Re: It's getting annoying..
In my dojo, where my wife and I are senior instructors, we ask 1st kyu and shodans to teach beginner classes. The reason we do this is that we believe that teaching a class of beginners is a good way for students at that stage of their development to organize their thinking with regard to basic technique. If you are so sure of yourself that you feel that the teaching experience is not helping you to grow then you should reexamine how you approach the art. After more than 35 years in Aikido I still have moments of doubt about technique and principles of Aikido. Also, I find it a challenge to present the basics in a way that doesn't confuse and helps beginners grow.
Finally, if you're Sensei has asked you to take on teaching duties you should be complemented that he/she has that much confidence in you. You should return his/her trust by concentrating on doing your very best. If you simply believe your Sensei is dumping on you maybe you should look for another place to train. Frankly, if I had a student who felt that way I would be glad to have him/her out of the dojo.