If you're asking... It's time to mention it. Otherwise you're going to let it grow into something larger than it needs to be. Your disfluency shouldn't be a secret. It shouldn't be an issue. You're uncomfortable with your stutter. Don't assume someone else will be uncomfortable because of it. But... I promise you that if you are uncomfortable with it, others will pick that up. They'll be uncomfortable because you are. Clear the air. "I stutter. My stutter is a source of discomfort for me."