How Old???

I was at the checkout of Tesco yesterday, patiently waiting for my items to be scanned through. The till lady, probably well into her fifties, suddenly stopped when scanning in a nice bottle of wine I had put in my basket.

She looked at me, then the wine and then back at me, before asking: "Have you got any ID?" I thought I misheard, so asked her to repeat. "I need to see some ID before I can let you buy this."

I was unsure if she was joking or not, so obediently handed over my driving licence. As she looked it over thoroughly, I commented "I turned 33 last week." She seemed satisfied that the licence wasn't fake and let me purchase the wine.

I am still unsure whether to feel insulted or flattered.