I have a presentation coming up this week too. To make it worse, it's a group presentation and I feel pressure that I might let my group down if I stutter. I'd prefer to go solo but oh well. I think it is to your advantage that everyone in the class already knows you stutter- use that to your advantage. If they already know you stutter there won't be any weird, surprised looks (I hate those looks). Power through it. And try to relax, meditate beforehand. And always keep in a cheerful, optimistic outlook even if you're in the midst of a block lol. That's my gameplan.