I've never been in that situation so haven't had to but when my stutter first developed in high school, I never spoke about it and the class presentations were awful. I blacked out during one and have no idea what happened but got a good mark for it so that's a plus. Maybe they took pity on me or maybe it was actually a good presentation idk Definitely email them and see if there is anything they can do to accommodate for you. They may not be able to as it may defeat the purpose of the presentation but its worth asking for