Nooria is a typical older sister—she's bossy and controlling and most of the time you just want to tell her to shut up. Everything about her drives Parvana nuts, including her "superior big sister smile" (2.7). But don't confuse their bickering with true dislike, because these two sisters seriously love each other—so when Parvana goes to prison with Mother, Nooria hugs her and whispers "Come back" (3.32), and when she does, we know she's not only concerned about her little sister's safety, but that she'd be devastated to go through life without her.
Though in many ways their lives are governed by war, Parvana and Nooria suffer from textbook sibling rivalry. They are super different from each other—Parvana's hair is stringy, while Nooria's is "long and thick" (2.8); Parvana is close with Father, while Nooria is close with Mother—and so while violence wages just outside their door, inside they bicker away like kids leading much more ordinary childhoods.
And while Nooria can definitely be a little snippy, to be fair she has a lot on her plate. She's Mother's right-hand man (er… girl), stuck inside day in and day out, helping with the little ones and household chores. And while Parvana risks her life every time she leaves the house, Nooria can't do the same since her body gives away her female identity.
In some ways, Nooria's age puts her in the position of being the person who has had to sacrifice the most since the Taliban's takeover. She's at the point in life in which her education is vital, with limited school-aged years ahead of her and a serious desire to follow in her parents' footsteps and attend college, in hopes of someday becoming a teacher. Nooria is ready to take charge and make something of her life, but instead she's held hostage in a tiny apartment with annoying little kids… which definitely wasn't part of her plan.
Because of this Nooria shows readers how much people lose under Taliban rule. While Mother has been pulled from her career, she's got the skills to return to it should that someday be possible; and though Father's lost his leg, the same is true for him. But Nooria is someone with drive and potential, someone who wants to learn in order to give back to society, but who instead is forbidden from receiving an education. We can feel the clock ticking for Nooria, and see how severely off-course the Taliban can pull people's lives.
Though Nooria cheers up a bit when the small school is formed in the apartment—Parvana notices that "a change had come over Nooria" (11.36)—she still jumps at a chance to get the heck out of Afghanistan, and even agrees to marry a man in Pakistan in exchange for her freedom. As she explains to her little sister:
There's no future for me here. (13.7)
And we can see why Nooria believes this—she has no freedom, after all, and the small joy she experiences teaching at the secret school can be taken away at any moment by the Taliban. Nooria has a chance to ditch the burqa, go back to school, and attend a university—and even if it means she has to marry a total stranger, she doesn't care. Nooria is outta there.