@Glomoro
Sleep is a big part of her character. Her whole character revolves around it. It's not unreasonable to say she has a condition which makes her sleep, or sleep easily. Maybe she doesn't but signs point to her having it.
Reading, though, yeah another sleep condition sounds more plausible. I think it'd be interesting to explore the possibility of her having something than just chalking it up to "She's tired because it's quirky!"