In 1870, Theodore Roosevelt, 11, met John Hay, 32, a colleague of his father's. Thirty-one years later, the latter would become his Secretary of State.
Theodore Roosevelt started a lifetime practice of weight lifting at the age of 12. A year later he started boxing as well because he was getting bullied.
[Side note: the presidential facts are going to start coming fast and heavy because TR's life is nothing if not a long string of interesting facts.]