Best female friends?

I don't think we have much evidence at this point as to what Charlotte's real feelings about Lizzy are (perhaps that will come later, but since this is a group read, we cannot "know" that), and whether they are such that Charlotte could get pleasure out of seeing Lizzy slighted. However, that's not the feeling I get from their dialogue. They seem like two friends secure enough in their friendship to tease each other, and it seems like that is what Charlotte is doing when she refers to the slight. I also get the feeling that Charlotte knows Lizzy enough to know that this would not be a sore spot for her.