I am usually unsure about a book that does one perspective in the first person, and the others in the third person. It doesn't always gel well, but at least the first person perspective isn't inside Nellie's head as she seems like she will be a very annoying character. The first impression feels like "Big Little Lies" which I liked, but the blurb description sounds a like it might be like "Girl on the Train" which I hated. If it is more of the first one, this is definitely something I'd love to read.