Sacagawea

This is my favorite trivia tidbit. No one I know has been able to answer it correctly. Who is the youngest person to appear on a U.S. coin?
Thinking...thinking...thinking. Time's up! His name is...Jean Baptiste Charbonneau.
Wait, what? Some French dude? You've seen him, but you've never heard of him.

Little Jean

He's been incorrectly identified as the only child to appear on U.S. currency. You can't tell from this picture (or most pictures) but his mother was seventeen. Yes, that's right. Lewis and Clark found the Pacific Ocean thanks to a teenager.
Sacagawea had a rough life. When she was twelve, she was kidnapped during a battle that killed several Shoshone. At thirteen, she was married off to a fur trapper from Quebec. By sixteen she was pregnant. At seventeen she lead the Lewis and Clark expedition across the West. And after that? We don't know too much. She could've died at twenty five or maybe ninety.

Sacagawea guided the most important expedition of the 19th century. If Lewis and Clark had failed, how long would it have taken to map the Louisiana Purchase? She shaped our country. She's one of the few teenagers (not to mention women and Native Americans) who gets mentioned in most textbooks. And yet they never tell you her age. None of these depictions show her as seventeen. Most people only know her from the coin so they have no idea.
We may not know what Sacagawea looked like, the correct way to pronounce her name, or even when she died. But we know she was born circa 1788 and the expedition began in 1804. She was young.
Why are we so reluctant to admit that teenagers have changed American history?