If it makes you feel better, I told Lois Bujold at Wiscon 30 that I wanted to thank her for many years of enjoyable reading, and her response was something along the lines of "what are you, 14?" I was almost 22 at the time and had been reading Bujold since... middle school? Though of course I understand that from her perspective I looked very young, and that's not so many years.

Probably one of the things mentioned below is what was going on with Jo Walton, but hopefully she'll realize you really did mean it was lovely. Wish I'd been able to catch that reading.