First of all, because The Glass Castle is a non-fiction memoir, it could be considered a coming-of-age story. The author opens the book speaking from her current adult perspective, looking back on her growth from childhood to adulthood. She then delves into her life story starting from the time she was only three years old.
Like any other story of growing up, of course Walls changes as a result of her circumstances. She matures. Walls' childhood is far from ordinary, and readers react to the details and descriptions of her parents (behavior as well as attitudes) with the thought that these people were abusive, at worst, and certainly neglectful, at best. The tone of the majority of the book, however, does not support either of these thoughts.
Because she never knew any differently, and certainly didn't know any better, as a child, Walls knew she was different from other children, but never suspected that her difference was a negative thing. In fact, one could argue that she felt a very distinct sense of pride in her family and the fact that they did things differently than others.
At one point she describes how her poor parents took care of them at Christmas, even though they did not have the money for fancy toys. One year, her father gives Walls the planet Venus:
“I never believed in Santa Claus. None of us kids did. Mom and Dad refused to let us. They couldn't afford expensive presents and they didn't want us to think we weren't as good as other kids who, on Christmas morning, found all sorts of fancy toys under the tree that were supposedly left by Santa Claus...
...We laughed about all the kids who believed in the Santa myth and got nothing for Christmas but a bunch of cheap plastic toys. "Years from now, when all the junk they got is broken and long forgotten," Dad said, "you'll still have your stars (39-41).
As she grow older, however, Walls begins to understand that her parents' differences from others are not necessarily something to be proud of. She becomes more influenced by her peers and observations of others than she is of her parents lessons and stories. When she is eating food from the garbage cans at school, she hides in the girls bathroom to hide her shame. Readers also know from the very opening of the story that Walls overcomes poverty in her adult life and has an estranged relationship with her mother. When she sees her mother from a taxi cab, rooting through garbage cans, she admits:
...when she looked up I was overcome with panic that she'd see me and call out my name...and my secret would be out (3).
In her lifetime, Jeanette Walls evolves from an innocent and emotionally sheltered childhood into a very well-rounded and savvy adult. This is a direct result of changing and maturing through her far from normal living situation as a child. It is clear that she loves her family throughout her life, and therefore harbors neither resentment nor anger toward them and the way they raised her. However, as an adult, she no longer gives her parents the free pass she afforded them as a child. She sees them through adult eyes and probably pities them, more than takes pride in them.