Rob.
When you speak in front of a crowd, you stand up and say what you have to. Don't make eye contact with anyone. If you find yourself doing this, scan your eyes across the audience.
If you start by being self conscious about anything , you're gonna muff it.
So, go in and say your piece. They are there to listen to what you say, not to judge you. If they do judge you then they won't learn anything and they are wasting their time and yours. best ignored.