@19parent – good luck to your daughter, she seems to fit the profile of the kind of student CMU is looking for (strong in math and with good social skills)!
If you haven’t come across it you might be interested in “Kicking Butt in Computer Science: Women in Computing at Carnegie Mellon University” by Carol Frieze and Jeria Quesenberry. It’s only a little over 100 pages and provides more detail about the CMU efforts to bring gender balance to computer science.
When considering CMU my daughter was initially turned off by the overall seeming geekiness of the males but her attitude changed during her accepted student visit after she went to a lunch with Junior/Senior women and got a feel for how they networked and supported each other.
There is definitely an “old girls network” with both students and alums that she’s been active in and proud of.