Life is, at first, difficult, shameful, unfamiliar, and frightening for Hà in Alabama. It's why she actually prefers the familiarity of her war-torn home nation at times.
Toward the end of the story, in the section titled "War and Peace," Hà describes how her teacher, Miss Scott, is showing only the horrors of the war to the classroom of American children and not the happier, peaceful aspects of life there. The children view photographs of terrified escapees desperate to escape Saigon. But Hà recalls the New Year holiday she loves and the delicious papaya from her own tree, both being happy aspects of life there even during the war. That's when she says:
"No one would believe me
but at times
I would choose
wartime in Saigon
peacetime in Alabama."
We also know that Hà had a close friend in Saigon, Titi, and that Hà was considered smart at her school there.
But in Alabama, because Hà is still learning to speak English (an immensely complex and difficult task if you're learning it as a second language) she is considered dumb at school, and it takes her a long time to make any friends there. It's embarrassing to do babyish academic exercises in front of the other kids in her Alabama classroom, and Hà is so stressed over what to do in the social microcosm of the lunchroom that she hides out in the bathroom and eats leftover food from dinner the night before--alone. A boy at school even taunts and bullies Hà, who eventually learns what the boy is saying as she masters more English, and she doesn't think that makes it any better to endure.
She also has to deal with the shame and discomfort of living off other people's donations. Even when her family was enduring tough times back in Saigon, they still always had beautiful furnishings and plates for their home. In Alabama, they don't. And when others try to extend their kindness by giving food to Hà's family, she has to smile and pretend to like it even though it tastes awful to her.
Taken all together, these difficulties help us empathize with Hà and understand that she longs for the comfort and familiarity of her home country, even though it's very unsafe there.