> The humiliation was when Sheila said she was best friends with Edna now.
The "now" is especially important. It implies the friendship they shared was never real. Sheila was just keeping her around while she waited for someone better to be friends with.
I don't think that's implied at all. In particular I don't see any evidence that the "friendship" with Edna was any more real. I think kids are just fickle sometimes.
