Well... age 10 is around when kids generally start to enter that fork in the road where they either say "I don't want to grow up!" or "I want to be a grown up now!" (In Vei's case, I'd assume the later, but I dunno). It's pretty much when they start getting to be independent though... and also when they start to worry a lot about fitting in and what "the norm" is supposed to be. They also begin to develop better reasoning skills, which can result in cheeky smart-alec remarks-- Vei seems to be chalk full of those (and it's delightfully entertaining, even if a good portion of it is just inner dialogue). They can also get to be very over-confident... something I definitely see in Vei. (10 is also around where puberty starts to happen... so for a young girl on her own whose body is starting to get all weird-- and with no motherly figure to shed light on the situation-- it must be rough.)

I think you still portray and grasp it all very well. She just seems very keen on things is what I was saying-- like being able to tell Cain was not only being mean, but manipulative. Using sarcasm was the biggest thing though. It's a pretty un-childish thing to do, but it's believable given her background (i.e. she probably had more exposure to it...). Given all that's happened to her, it doesn't seem farfetched for her to be more mentally mature-- I just have yet to see the problems that are caused by 'trying to grow up too quickly' affect her. It's early in the story, so it's fine.