Like /u/skeptic135 said, practice is key. The more you can the more you'll relax. Ask your friends/teachers for help. If you need more people DM me, I'll be happy to help. Also, try to establish a bit of a rapport via email or some other means if you can. Show that you're thoughtful and interested before the interview so that won't be your first impression. But most importantly don't stress about it. I've hired a lot of people over the years and I can't imagine prejudging someone for stuttering, but then I a stutterer so I'm a special case I suppose. Regardless, don't assume they're judging you. That'll just make you more nervous. Most people are nicer than you think. Just imagine how you would rract were the roles reversed and you'll see that stuttering isn't the end of the world. Good luck!