First Person (Central Narrator) / Bone Boatwright
It's pretty clear that Bone is telling the story of her childhood from her point of view, but here's a question to get you thinking: how old is she as she's telling it? We know that she talks about the events of the book in the past tense, and with some foreshadowing of things to come, so we assume she's in some future time.
Okay, big deal, literature does this all the time, right? But the narration in Bastard Out of Carolina works on two levels at the same time: Bone both a) looks at the events of her childhood from the vantage of adult understanding and b) tries to convey how she perceived these events as a child. Here's what we mean:
Let's compare two quotes. In the first one, Bone is inhabiting her ten-year-old voice while trying to find the words for what Glen does to her when Anney isn't around:
It wasn't sex, not like a man and woman pushing their naked bodies into each other, but then, it was something like sex, something powerful and frightening that he wanted badly and I did not understand at all. (8.26)
We know that our narrator is in Ten-Year-Old-Bone Mode, because obviously Mature-Narrator-Bone has a better understanding of sex than "a man and a woman pushing their naked bodies into each other." In fact, she is using naive language precisely to show us how confusing the situation was for her at the time. A better way to describe what's going on here might be that Mature-Narrator Bone is channeling the language and thoughts of Ten-Year-Old Bone.
Now look at what she says when she is "looking back" on Glen and Anney's courtship:
More than anything in the world, Glen Waddell wanted Earle Boatwright to like him. (1.53)
Now, Bone wasn't even present for this event, and she certainly wasn't inside Glen's head reading his thoughts. Even Ten-Year-Old-Bone interpreting the story of Glen and Anney meeting probably wouldn't be able to read this much into Glen's character, so the insight must come from Mature-Narrator-Bone.
So really, think of it as two Bones: the child in the story, and the adult narrator. The point is to pay attention to the moments when Bone gives us her child-judgments and her narrator-judgments, because the novel is subtly balancing the experiences of childhood with the understanding of adulthood.
This is especially important when you think about the fact that this is a novel that deals with children not knowing how to react to or talk about sexual abuse: it's important that we get a sense of Bone's helplessness through her language (or lack of it) and her limited understanding of the situation.