Firstly, I know you're going to kill it regardless, so take a deep breath and lead with confidence. Secondly, when I have to give a large presentation at work or a speech in front of a group of people that do not know me as well as my closest friends/family I often like to start by casually and confidently reference the fact that I do indeed have a stutter and that it may come up while I'm speaking. For me, the worst part of is when you start to stutter and people start giving you 'that look' where they try and figure out what's 'wrong' with you and why you're speaking that way, but most people (like our friends and family) are aware of our stutters so don't even notice when it's happening. By opening up with a casual reference about the fact that I may stutter I feel it clears the air and tackles the problem head on, allowing people to actually listen to what I'm saying rather than sitting through my presentation wondering why I sound that way. Best of luck regardless!