“The only time she could feel sympathy for her sister was when someone else spoke sharply to Louann or made fun of her. Otherwise, resentment was always boiling under the surface.” 

These lines show Amy at the beginning of her character arc. Amy’s resentment toward Louann is due to guilt, both for how she treats Louann and for not wanting to care for her sister. Amy will grow over the course of the book, but for now, she desperately wants a different life and experiences she deems normal.

“‘All set.’ If those words meant ‘Do you feel great about leaving?’ she really wasn’t set at all. But if they meant ‘Do you want to go?’ then she was all set indeed.” 

Amy thinks this before leaving to stay at Aunt Clare’s house, showing her inner conflict. She views Aunt Clare’s house as a refuge from her guilt and believes running away will make everything better. Amy’s reluctance to leave her family, however conflicted, foreshadows her ultimate decision to reunite with Louann and her parents.

“But, even little kids can learn to help themselves, and they’re happier because of it.” 

Aunt Clare says this while talking to Amy about Louann. Here, Aunt Clare plants the seed for Amy to start considering Louann as a person and sister, rather than a burden. This line also plays into the theme of different abilities and disabilities. Louann may have unique challenges, but she is still able to do things in her own way. Sometimes, those ways are more effective.