The City of Ember
How we cite our quotes:
Lina had always liked her. Even when she was little, Clary did not treat her like a baby but gave her jobs to do—pulling up carrots, picking bugs off cabbages. (4.38)
Youthful is as youthful does, and Lina shows early on that she's ready to be treated like an adult. Well, most of the time, anyway. Being able to pick bugs off cabbages is a lot simpler than taking care of your family, especially when that family includes a rambunctious toddler.
Colored pencils! Lina had not seen colored pencils in any store for ages. (5.10)
Even though Lina's old enough to have a job and support her small family, she's still a kid in a lot of ways. She loves the idea of having colored pencils so much that she sets out to find some after hearing them mentioned in a conversation, and she is willing to pay more than she should for them. This is one of the things we think is a bummer about Ember: every kid should have access to colored pencils, right?
She had found something strange and important: instructions for something. But for what? And how terrible that Poppy had found it first and ruined it! (7.6)
That's the thing about kids: you've gotta keep an eye on them if you don't want them making a mess or possibly getting hurt. They probably have the concept of baby proofing a living space in Ember, and we're guessing that Lina's apartment is pretty safe in general, but obviously there was no way for them to know in advance that an important message from the Builders would be hidden in one of their closets