Sensitive, private, intuitive: Lilia as a kid is about as sweet as they come. She's the kind of kid parents can depend on to treat guests respectfully, as she does with Mr. Pirzada.
She always takes his coat when he visits and hangs it up for him. She prizes the candy he gives her so much that she tucks it all away in a special box that used to belong to her grandmother. (You can also say she's sentimental.)
And she knows immediately why Mr. Pirzada offers to go trick-or-treating with her and her friend: because his own daughters are missing (WMPCTD 71).
Which is why it's kind of surprising how she ends her story about Mr. Pirzada—by throwing away her candy after she learns that he's rejoined his family in Pakistan. Her candy was her connection to Mr. Pirzada, and now it's just a painful reminder of his absence.
Grown-up Lilia looking back on herself is really like child-Lilia, only more aware. You'd think that extra layer of awareness would mean that adult-Lilia knows more. And she does. Through her, we get a critical view of how American culture acts on child-Lilia. For example, it's Lilia as a narrator who's able to answer her father's question about what they learn in school. She points out that in Lilia's American school, it's all about US history and geography—of course.
But we get that when she describes all the US history stuff, she's also critical of it because it doesn't seem relevant to her real life and to what Lilia's going through at home with everyone's attention to the war in Pakistan. (Hey, if this is how you feel about history class too, then we sympathize. That's why you should head over to our US history site. We're not above shameless plugs.)
This is stuff that child-Lilia doesn't really know yet, so that's why we need the adult-Lilia: to make her story about more than just an old man who gives her candy.