The stereotype of someone with ADD was a grade-school aged boy, flying around the classroom, knocking things over.
Girls tend to have attention deficit without hyperactivity.
Even those with hyperactivity have their symptoms overlooked or misattributed. And many women came of age before it was recognized that ADD could continue into adulthood. Girls with ADD without hyperactivity may be able to compensate during childhood. Structure imposed by school and parents can help her organize when she cannot do so by herself. Girls may be more taken care of and their lack of accomplishments not as much a concern to the adults around her.