To answer the question, you do not need to disclose your stutter during an interview. As far as how the interview went, it sounds like it went well! If you hadn't posted this question in this sub, it would literally read like a normal interview. Sure, they may have assumed you might have been nervous. But, it's up to them now on who's right for the job. In my experience, people don't actually give a shit. But we think they do. You did the hard part. Be proud and look back on it as awesome experience. We're all super proud, thanks for sharing.