St. Johns in Houston is the most exclusive private school in the city. About 75% of the school is admitted as a legacy. The remaining 25% all have parents that spend tons of money donating to the school and to any other cause that will catch the attention of the admission committee and higher ups at the school. And this is just to get in for kindergarten. In order to get a spot after kindergarten, your parents need to be C-suite level rich. St. Johns will admit a tiny handful of kids who are clearly academic prodigies. I worked with a guy whose son got in for high school. The kid got a perfect score on the SAT without doing any test prep programs. But the school is nothing more than a center for the privileged to buy the best education in the city for their children.
Holmes' father was a VP for Enron and very politically connected. He must have leveraged relationships to get Holmes into St. Johns. St. Johns kids are all exemplars of the maximum privilege available in our society. The guy I worked with (a real estate attorney) whose son went to St. Johns would take him skiing in Vail every winter. His son would get made fun of at school because he took a commercial flight to Breckenridge and rented a generic condo. Most of the kids would fly on their parent's corporate jets and stay in million dollar ski chalets at exclusive resorts like Sundance and Telluride.
In that world of privilege, all the kids presume that they are destined for the C-suite. It is not hard to see how Holmes would feel compelled to "fake it until you make it" in the environment she grew up in.