Just a momentary thought. In esse the US has already had a female president, that being Edith Wilson the second wife of Woodrow Wilson. When President Wilson fell severely ill from stroke and could not function anymore she secretly took over. As the White House says

https://www.whitehouse.gov/about-the-white-house/first-families/edith-bolling-galt-wilson/

"After the President suffered a severe stroke, she pre-screened all matters of state, functionally running the Executive branch of government for the remainder of Wilson’s second term."