Obviously depends on the professor, but I would imagine most would be quite understanding of it. I mean I didnt just not have to do it and get 100%, she gave me the option of writing a paper instead so I happily took it. Id advise you to just talk to your lecturers about it if you have any presentations etc for that module... And try not to worry to much, when you go to college chances are you will meet people with much more serious disabilities and challenges in their life. In my case people I have met in college have been much more understanding of it than ones from back in school for example. So dont fret dude, chances are college will be the best days of your life, stutter or no stutter.