Whatever you decide to do: stay or go it is fine. Speeches scare fluent and dysfluent alike. If you stay: Do you think you could write yours out word for word and read it aloud? I know a lot of people have no trouble with reading—or at least much less trouble. They discourage that but you could tell them your situation ahead of time I bet they’d understand. Assuming you do stay— your first speech might be about stuttering. Usually the first thing a person does is explain they stutter, then proceed with a presentation. From what I’ve heard the toastmasters group is very supportive. They are all there to get better.