Yup, been there and remember those presentation days all too well. I know how embarrassing it is but you just have to say fuck it and stutter. It's a few minutes that seems like a lifetime but once it's over it's over. Also believe me when I say no one really cares and no ones really paying attention. You'll stutter and feel embarrassed, but once your done the next group will go up, and the next day no one will care that you got up there and stuttered. Hope this helps. I know the anxiety of having a presentation, trying to let the group know exactly what part I'll present, talking to the teacher. People who don't stutter think they're helping you in some way by making you talk lol. Like they're helping you conquer a fear😂 when it's really a speech impediment.