bright young things or kick-started

Writing for the Journal of the American Revolution, Tod Andrlik presents a frankly mind-boggling yet surprisingly elementary, knowable list of the ages of the important players, the Founding Fathers and their foils, when independence was declared back in 1776. I suppose that I had my preconceptions of a lot of venerable figures assembled assembled, romancised on the obverse of currency and in other legends, but to survey the facts and figures is really disabusing. Many were quite young at the time:

James Madison was 25 years of age
Marquis de Lafayette, 18
Alexander Hamilton, 21
James Monroe, 18
Aaron Burr, 20
Betsy Ross, 24

I had no idea, and it's like finding out that Juliet and her Romeo are meant to be fourteen and fifteen year olds. George Washington, Sam Adams, Paul Revere, Thomas Jefferson and Benjamin Franklin were all significantly older, but no ageism was to be found on either side (nor implied here neither). Perhaps the sole exception was in setting the minimum age for presidency at five-and-thirty.