In a word, yes, she likely had a leg up. The credit mostly goes to her, not you or the book you used.
As the father of a boy with an extremely strange developmental reading profile (couldn't read a thing at age seven even after much one on one tutoring, to reading at an eighth grade level at nine) I learned a few things talking to many other parents and professionals. The most important is that no one method works for all children, as they each learn to read in their own way. My boy was definitely a "whole word" learner, and phonetics was a complete disaster for him. Other kids are clearly the other way round, and many kids do a combination of both.
Secondly, intelligence has nothing to do with it. Dyslexia is caused by many factors, but general intelligence really isn't one of them.