I wouldn't worry about too much. I have no clue about table top gaming, but generally with "hobbies," it's people coming together over a shared passion. They don't care who you are as long as you share their activity. If somebody gives you a hard time about it, well they're just a jerk. I honestly don't think anyone's made fun of me about my stutter since high school, and that was 7 years ago. I know it's easier said than done, but just power through your difficult moments. Most people will have the common courtesy to be patient with you, which is all we can really ask. If somebody does say something, well then do what you think is best. You can ignore it. You can tell them that you have a stutter that you can't control. You can t-t-try to make a snarky comment back. Whatever. It's them who's being being the jerk. Most good people will recognize that, so I wouldn't let it get to you too much.