List of presidents of the United States by age
The median age upon accession to the presidency is 55 years and 3 months. This is how old Lyndon B. Johnson was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president at the age of , following William McKinley's assassination; the oldest was Donald Trump, who was old at his inauguration. The youngest person to be elected president was John F. Kennedy, at of age on election day; the oldest was Ronald Reagan, who was old at the time of his election to a second term.
Late bloomer
Václav Havel, born in 1936, was a playwright and writer with an interest in human rights. He became the voice of the opposition in Czechoslovakia in the 1980s and President of Czechoslovakia at age 53 after the collapse of the communist regime in 1989. Ronald Reagan, a former actor, union leader, and corporate spokesman, was first elected to public office at 55 when he became Governor of California and remains the oldest man to have served as U.S. President. Melchora Aquino was an uneducated Filipino peasant woman, the mother of six children, who became an activist in the fight to gain independence from Spain. Known as the Grand Woman of the revolution, she was 84 when the Philippine Revolution broke out in 1896. Silas C. Swallow was a minister who became a Prohibition Party activist in his sixties. Marjory Stoneman Douglas's career might also fit. Her first environmental work of note occurred when she was almost 60, at 78 she founded "Friends of the Everglades", and she continued until she was over age 100.