That is surprising, yeah... perhaps she stumbled upon the Kirby cartoon recently? Or did you use to play Kirby a lot on your SNES when you were younger, perhaps? I know my mom recognised most characters from games I used to play fairly well, too; at least, most of the time up until I started playing games in my own room rather then the living room.
When I still had consoles (Master System, Mega Drive) in the living room, mom used to play practically everything I did. I often drew the characters from the videogames I played, and she was usually able to recognize who it was I was drawing, characters like Sonic (of course), Alex Kidd, the Kiwi from New Zealand Story, Dynamite Headdy, Lemmings, or even Dark Force from Phantasy Star 2 (I was stuck at that battle for a fairly long time, you see. =P).
Also, see edit. =P