The Plight of a Woman With the Last Name of Kelsey

Today I had an experience that unfortunately is not uncommon. I went to drop Christian's suit off at the dry cleaners. The lady kindly asking me, "And what's your last name, Ma'am?"
"Kelsey." I answered.
"You're last name," she clarified.
"Kelsey." I answered again.
"Ok," she said skeptically, assuming I didn't know the difference between a last name and a first name.
"And your first name?"
"Dagny. D-A-G-N-Y" I automatically spell my name because everyone always asks me to spell it anyway.
At this point the lady looks up at me very confused. "That's your first name?" she asks, once again looking at me like I have no idea the difference between a first and a last name.
"Yup. That's my first name."
"Ok." she says in a way that tell me she is clearly unconvinced that I've told her the right name.
I promise you dry-cleaner lady, I was not trying to trick you. That really is my name.