Gladwell includes the story of Jamaica to demonstrate how the principles of his book have impacted his own life.  Throughout the book he deftly shares stories of remarkable people who were different than others and took advantage of opportunities that they saw that others didn’t.  The story of Daisy Nation personally affects him, because her success became his success.

Gladwell insists that we have all too easily bought into the myth that successful people are self-made; instead, he says they “are invariably the beneficiaries of hidden advantages and extraordinary opportunities and cultural legacies that allow them to learn and work hard and make sense of the world in ways others cannot.” (enotes, http://www.enotes.com/outliers-the-story-of-success)

Gladwell wants to make the point that extraordinary people are those who take advantage of the extraordinary opportunities they are given. Gladwell speaks candidly about why he included this story.

It is not easy to be so honest about where we’re from. It would be simpler for my mother to portray her success as a straightforward triumph over victimhood. (google books)

Gladwell’s point is that the story of his mother’s success involved not just intelligence and guts, but also luck.  For example, his aunt and mother both earned scholarships but his mother did not go until another girl earned two and gave her one. Gladwell points out that light-skinned people also had an advantage in Jamaica dating back to its days as a slave plantation.

Slave owners often had children with their black slaves; those children were given preferential treatment and allowed to be house slaves instead of working in the fields. This afforded them education, societal mannerisms, and further advantages from that point on. (http://www.enotes.com/outliers-the-story-of-success/epilogue-summary )

Since Gladwell had light-skinned ancestors, those ancestors had a history of advantages. This proves Gladwell’s point that it’s about luck, change, and history.