This is a good length for a beginning chapter book. It is short enough that it won't overwhelm readers making the transition from picture books into the longer format of chapter books. Other good points are that Lilly's friends include both boys and girls and there is a good mix of families (single-parent, two parents, a family with a grandmother living with the younger generations). I especially like that the friends make a point of saying they are not going to fight anyone, even the bullies - and then the bullies are frightened away by something that happens accidentally. The book was written by Brenda Bellingham. You can find more information about her on the publisher's webpage for the book.
I read an e-book provided by the publisher through NetGalley, but it is available in stores.