Etta is forced to deal with quite a bit of death. From the deaths of others she learns about to the deaths that happened in front of her. Coping with this loss of life is not a normal situation and she is forced to try and understand why life is that way.
Usually events resulting in complex trauma occur in childhood while an individual’s personality & coping abilities are still developing. Children don’t have the same coping abilities that adults do & if they lack support, or models of healthy coping, they may respond in ways that aren’t healthy & adaptive, resulting in trait-like symptoms. When children are young, their experiences are totally normalized & only much later do people realize that other families are different.