Where I studied in USA there where plenty of mature people in my class. This one gentleman had the benefit of hindsight; he had tinkered with early computers,

Where I studied in USA there where plenty of mature people in my class. This one gentleman had the benefit of hindsight; he had tinkered with early computers, and had seen its evolution. (This was with regards to Bachelor's and Master's degree, though I don't see why they wouldn't accept mature people to PhD programs).