When I was in school, I told all my teachers I have a speech impediment and doing presentations, reading out loud, etc, will be hard for me. I tell them its something I'm born with and can't change it. As an adult, I tell every job. I've never had a teacher give me less points on a presentation because of the stutter. It would be like giving someone less points for a lisp. I really think talking to your teacher is the best option here. Explain how you're feeling. I know not all teachers are good people, but I would imagine 99% of them would be totally understanding.