Do you tell people that you have a stutter?

Do you tell people that you have a stutter? Whether it's your teacher, a friend of a friend, a classmate you've been paired with, your date... anyone! Do you just talk and stutter without saying a thing about your stutter or do you actually tell them? I feel like most people don't know stutterers exist, so I always believe they just think we're nervous because we're talking to another person. That's why I don't know whether to tell those people I'm meeting before anything else. The truth is that we stutter, not that we're anxious or anything.