Physics faculty can approach even male to female ratios, at least at some colleges. By inference, then, it seems young women must be reasonably well represented as students in undergraduate physics programs. Notably, women have often contended for Apker Awards (the top recognition for undergraduate research in physics) in recent years:
https://www.aps.org/publications/apsnews/201908/apker.cfm
https://www.aps.org/publications/apsnews/201808/apker.cfm
Regarding college selection, your daughter may want to consider schools at which all majors are made available to all students without significant restrictions.