I would definitely tell him. 99% sure he’s not going to care. Trust me most guys are just thrilled to be on a date with someone they are connecting with (you said you guys hit it off). Being open about it accomplishes many things: 1. Frees you from the burden of trying to be fluent 2. Leads to meaningful, interesting conversation as I’m sure you have good stories about stuttering and he’ll no doubt have genuine questions 3. Makes you stand out from other people he’s dated 4. Gets it out in the open so there’s no awkward misunderstandings like “he thinks you’re cold” 5. Vulnerability is contagious. Maybe he’ll share something personal with you and you guys will bond over it 6. Tons more but too many to name Bottom line. Do it and have fun. Your stuttering doesn’t define you. Get it girl!