The other day I was on a date and stuttering on my order and waitress started going "uhhh..." and chuckling, not knowing what was going on. I knew she wasn't trying to be rude, just a bit ignorant or what was going on. I told her I have a stutter and then continued stuttering out my order. She became real quiet and listened intently. I think your response was perfect and hopefully it lent a lesson. Sounds like her coworker agreed lol.