https://en.m.wikipedia.org/wiki/Mary_Kenneth_Keller
A Roman Catholic nun was the first person (not woman) in the U.S. to earn a PhD in computer science, and tied for first if we mean “doctorate”.
This was in her 50s, after having previously earned an undergraduate degree in mathematics and a master’s degree in math and physics, around ages 30 and 40.
Then, with a PhD earned that late in life, she founded what was among the first computer science academic departments at a small college, and ran it for two decades, and published in the field.