"Like I ever had a bedtime. Ma been telling stories again?" It's a rhetorical question, and a useless one even if it weren't.

A) Ma would always tell stories, if Kaylee would listen, and,
B) Yes indeed, at one point or other Malcolm Reynolds did have a bedtime.

But Kaylee wasn't looking for him for anything resembling family history, and Mal breathes in and out evenly.

Placid: "What do you need, Kaylee?"