How does the author use foreshadowing in The Summer of the Swans?

In Chapter One, we learn that Sara is a typical teenager, uncomfortable in her own body and unhappy with her life. There is foreshadowing in her discussion with Charlie about the summer, that it feels different than before. Many teenagers reach a point in their lives when the same old childish stuff is no longer fun and exciting like it was before. Not only is this foreshadowing of changes that are coming for Sara, but it also touches on the theme of coming of age. Charlie's broken sucker and his dependence on Sara to fix it also foreshadows future conflict between the siblings.