When I was your age I often worried about speaking to strangers and stuttering. I would feel embarrassed and ashamed to some degree. Even now years later it is an issue for me. You’ll have to basically force yourself into those social situations and not worry about what other people may think. Repeat what you’re going to say over and over in your head as well. That little trick has helped me significantly over the years. Just don’t be afraid to be yourself. Your stutter is apart of you. Embrace it. Also, nowadays if you pretend to cough the customer will back up and not even want to speak with you. (Thanks Covid.) So if you want to avoid a conversation, definitely do that. Also, my first job was in Fast food. McDonald’s to be exact. Good luck, fast food is a beast.