Winnie Foster comes into the lives of the Tuck family under abrupt circumstances, seemingly out of nowhere; she meets Jesse at the river, and Mae and Miles show up shortly after. Winnie is then essentially kidnapped by the Tucks. Angus Tuck says this upon first meeting her, as an indirect reference to the fact that the family generally does not interact with mortals out of self-preservation. This is before realizing that she is much much more than a "honest to goodness natural child" he deems her to be. Winnie is only ten years old, yet she transitions quickly from rejecting fairytale stories to believing the Tucks and their story of immortality. She is still a child, yet soon she is faced with the choice of living a normal life, and joining the Tuck family in an everlasting life.
In chapter 9, After Angus says these words, he tells Winnie that she is the best thing that has happened to the family in eighty-seven years. These initial welcoming interactions with Jessie's family, in which they trust her to keep their secret, is the beginning of the love and acceptance she feels in their presence. It is the precursor to the monumental choice she has between remaining a mortal child and drinking the water from the everlasting spring and joining the Tuck family.