My stuttering gets worse when I'm talking with people I know especially family because I naturally want to talk more infront of them not because im nervous. I'm usually quite reserved with others and they see me as very quiet but I'm not that at all lol. My advice would be to know what your talking about, study and practice until you have no doubt you know your stuff inside and out. This helped me out because I didn't care if I stuttered when I had confidence in the material I was speaking on. Take your time. Tapping on cards or a notebook helped me get over some bumps in the road. 2 birds 1 stone. Educate them on your presentation and your perseverance by embracing the stutter and keep on trucjing. Also don't focus on the duration of the presentation. Take your time to educate your class. Hope this helps you even a little. Good luck!