Even though it's always obvious, I have never revealed my stutter...until my last interview. It was for an internship I really wanted, so naturally, I was freaking the fuck out. When I was asked to tell them about myself, I started rattling off who I was (without stuttering that bad imo), but was stopped by the interviewer who blatantly asked me if I was nervous. I guess my glasses were fogging up bad lol. That's when I explained that I was nervous mostly because I had a speech impediment, stuttering. I made sure to include the fact that it was a speech impediment to avoid the all-too-familiar "Oh it's okay I stutter sometimes too" response. He was clearly taken by surprise. Now that the people in the room were aware of my stutter, I spoke with much more confidence. I highly recommend you mention it.