In 2021, Joe Biden became (and may probably remain the only) the first person from the Silent Generation to become President of the United States.
Elizabeth Blackwell became the first woman to earn a doctorate in medicine in America after the dean allowed the male student body to vote upon her entry. The students thought it was a joke, and voted yes.
The first woman to testify before US Congress was American feminist Elizabeth Stanton.
Hiram Revels was the first African American to serve in Congress. Becoming a senator in 1870, he represented Mississippi which was ironically the state that Jefferson Davis represented.