If they know that you stutter, they will expect you to do so. As a non stutterer, most people are not assholes. Keep calm, and keep it in your mind that we will not kill you if you stutter. Or mess up. Its ok. The vast majority of people are nervous before a presentation, not just you. I have been lucky enough to have an immense amount of confidence, so this is not the case for me, but I know the feeling of being afraid of fucking up in front of everyone all too well from other situations. If you want to, dm me and i can give you advice about presenting shit, I have to do it a lot.