Hey, I'm also having stuttering problems for many years, it has got better over time but still, making phone calls is terrible, Presenting something is even worse. I know that stuttering can bring your self confidence down really quickly. Mostly people don't laugh about it (if you are in high school then it's tough), most don't even care- they have their own problems to think about :D. Maybe this could work for you: Don't think about how will you say it but think about what will you say. So, instead of focusing your energy on how you want to speak, focus on what you want to say. Also don't be shy to pause between words or sentences. It gives time for the listener to "compute" everything you have said so far. I want to believe that in the interview they won't care how you speak, but focus on what you say.