Is it that Donkey Kong you kids are always playing?

from here (source image tweeted by @lawblob)

Oftentimes online you'll see people joking about grannies being unfamiliar with technology. This isn't that. This is joking about grannies not being familiar with Sonic the Hedgehog, while quite possibly everyone else is. So if your threat model is your grandma, then that seems like a perfectly reasonable security question to use - otherwise try something else.