The first time I had to teach a class I was so nervous I couldn't speak. That was about five years ago. Since then I joined Toastmasters, and continued teaching. I won two Toastmasters speech contests. Gave a few research presentations, some of which went pretty well some not so much. But most importantly I have become lot more confident at public speaking. Teaching this semester so far has been as smooth as silk. Congratulations on your speech. I hope you have more such moments.