I got over my introversion in college (I was a "nontrad", i.e. a student over 24 years old per the state school definition, at least) - I just decided there's no way that anyone was paying attention to me anyways. So I might as well just say what I want, since it was almost the same as talking to myself. It worked really well in school. Once I got out and rejoined the working world, I had some fear regress because I realized I was around people that were listening again. But I had enough confidence from practicing at college that I could hurdle the second hump in basically the same manner.

It's like racing through the heliopause of the sun. You're Voyager 2, riding the solar waves. You know you're about to do your first presentation. It's going to be rough. And it is. But then you're through it, and you're in interstellar space from now on, there's no pressure.