Yea I do this too. People usually say things like that to break the tension, but I use it as an opportunity to let them know I stutter. It used to piss me off when people said things like that, but most of the time they are just truly unaware and don't mean anything by it. One time I was crossing an international border and the crossing guard asked me what my name was, and I blocked on my last name. So then he says, "You sound nervous." I just responded with, "No, actually I just have a stutter." It made him feel pretty stupid, but sometimes border guards can be a little antagonistic, so it felt good to make him uncomfortable lol. My last name also starts with a B and it can be a stumbling block at times. Given the opportunity I usually introduce myself with my first and last name as one fluid name, instead of just saying my first name and hoping they don't ask my last name. I find its difficult to start with a B sound, but if link the two names together, it seems to flow better.