It's normal to be afraid of communicating with other people, and this fear increases exponentially when there are a large number of people listening to us. While I haven't been in situations similar to yours, I've had to speak and answer questions in front of others (though not as many). What worked for me was simply memorizing my speech and delivering it; in those moments, stuttering was the last thing on my mind. I've been in similar situations on occasion, and the result was always the same: either I spoke based on what I remembered or I focused so much on answering the questions that I could respond without difficulty, as if the stuttering disappeared because I wasn't concentrating on it. All my attention and intentions were on giving answers. As for advice, if you encounter word blocks, just take a deep breath and then say the word that wasn't coming out. Also, I'm not sure if it helps, but try speaking softly and slowly, and focus on starting the speech in a "smooth" and slow manner. Finally, I would recommend practicing what you'll say; you can do this in front of a mirror or with a friend. This will help you feel more confident, so when the moment comes, you won't have a painful stutter. That's all; I wish you the best of luck with the internship!