Only if you're comfortable doing so or if they ask. In more serious setting like an interview or meeting it's better to disclose because then the audience isn't wondering what's happening and you're not wondering if they're focusing on your speech or not. I'm 30 and realized recently that people don't care that i stutter. I say what I need to and the conversation moves on. The most important thing is that you carry yourself as if the stutter doesn't bother you. If it bothers you it'll bother the audience.