The USA academic staff ranks are different to the UK system.
The student's best friend, Wikipedia, offers this explanation,
"while "Professor" as a proper noun (with a capital "P") generally implies a position title, the common noun "professor" in the US appropriately describes anyone teaching at the college level, regardless of rank; also, as a prenominal title of address, it can be capitalized without implying the title rank."
https://en.m.wikipedia.org/wiki/Academic_ranks_in_the_United_States
Whereas in the UK, Professor is a position in a university marking the pinnacle of an academic career, so profs here tend to be older, whether male or female! It's unusual for someone in the UK system to reach Professor at an age under 35, unless they're absolutely stellar.
All the best,
Keith