Who was the youngest American President in U.S. history?

Okay, pay attention, because this is confusing if you don’t.

Kennedy at 43 was the youngest person elected president, but he wasn’t the youngest president.

Roosevelt was vice president when McKinley was assassinated, elevating Teddy to the presidency when he was a mere 42.

That makes Teddy Roosevelt the youngest American President in U.S. history. Make sense?