As it turns out, many Founding Fathers were younger than 40 years old in 1776, with several qualifying as Founding Teenagers or Twentysomethings. And though the average age of the signers of the Declaration of Independence was 44, more than a dozen of them were 35 or younger.
“We tend to see them as much older than they were,” said John Adams biographer David McCullough in a 2005 speech. “Because we’re seeing them in portraits by Gilbert Stuart and others when they were truly the Founding Fathers—when they were president or chief justice of the Supreme Court and their hair, if it hadn’t turned white, was powdered white. We see the awkward teeth. We see the elder statesmen. At the time of the revolution, they were all young. It was a young man’s–young woman’s cause.”
See a list of the signers (and other important Revolutionary figures): How old were the Founding Fathers: The leaders of the American Revolution were younger than we imagine. – Slate Magazine.