If computer science is roughly 1/2 of the bachelor’s degree in the field at UW and a little under 1/3 of the degree at William and Mary, I think that is a reasonable rough indicator that a typical person majoring in computer science at UW will come out knowing about 50% more computer science than the same person would while majoring in computer science at William and Mary.
Beyond that, it depends how many computer science electives William and Mary offers, that are not required but that could be taken to correspond to the additional topics covered at UW.
One can continue learning in any field beyond undergrad, of course.
Still, if your daughter is committed to computer science, I think UW is the better option.
It is unfortunate that gender should play into this at all, but I think that a young woman is better off being as technically advanced as possible when she graduates. (I write this as a woman in a STEM field.). In future years, this may matter less, but there is certainly a lot of publicity about the poor treatment of women in tech companies. Advanced knowledge serves as a partial shield from this (but only partial). I look to the situation to improve, but four years is a short time horizon.
Best wishes to your daughter!