Compliment or not?

The other day I dropped off a prescription for my wife at the pharmacy. The middle aged person working there asked me for her date of birth (for insurance purposes I assume). The exchange went like this:

Pharmacy worker: "patient's date of birth?"
me: "day, month, year"
Pharmacy worker: writes down date, I can see that she writes the correct date
Pharmacy worker: pauses, looks closely at me from just across the counter, makes a slight frown/thinky face and says "uh...so this is for your....mother?"
me: "uh....no, my wife"
Pharmacy worker: "oh....uh, okay" and she just moved on with no further comment

My wife and I were born the same year, so the date of birth I gave for her is very close to my own. The woman working there has been there for years, I have seen her a bunch of times. She is no nonsense to the point of being quasi-rude. Doesn't flirt or exchange pleasantries with anyone so I don't think she was trying to be nice to me.

I don't see how she could have thought I was young enough to have a mother my age....that would mean she thought I looked 20ish years younger than I am.

Would you think of it as a compliment? Or is it so far out there you would only think of it as evidence the woman had a major brain fart?


Compliment or not?