As a novel, this would make a really good short story. Or novella. Or something shorter than the 222 pages I forced myself through.
There's nothing wrong with the writing. There's nothing wrong with the idea. But how the narrator forged her connections with some of her friends is left sketchy at best. Besties with a ragpicking street person? Totally out of character, as I read her, and totally out of her social class, which was important at that time...but okay, I can stomach it. She's a kind person and that comes across in the narration.
The twist that comes toward the end can be seen about a mile off, which kind of takes the twist out of the twist, if you get my meaning.
Finally, the language is awkward in some places, at least to me, an old French teacher. I looked through the publishing information to see if it was translated from French into English, but I didn't see that anyplace. If the book was translated, errors that should not be made by a competent translator crop up from time to time; if it was originally written in English by a non-native speaker, there are common errors made by English learners that should have been caught by an editor or proofreader. This is a very common gripe of mine: Who's editing this stuff? Anybody? Bueller? I feel like the voice crying in the wilderness for better close reading of material to be published. I truly believe that a) figuring people won't notice shoddy usage, poorly chosen words, etc. or b) assuming it just doesn't matter in the larger scheme of things is just plain insulting to the reader. and I, for one, do not take kindly to being disregarded in this manner by people whose job it really is to make sure that doesn't happen.