Janet Yellen will be the first woman to head the Federal Reserve (upon confirmation). She was born in August 1946 and graduated from Brown in 1967 (I assume in May), when she was not yet 21 and earned a PhD in 1971 (at age 24 or 25). Apparently she skipped a year of junior high school by participating in a "special progress" program.

http://www.businessinsider.com/janet-yellen-teenage-years-2013-10
Janet Yellen's High School Friends Remember Her As Interested In Everything And Imperturbable
ROB WILE
Business Insider
OCT. 9, 2013

Quote
Born in 1946, Yellen (who kept her name after she married) attended Fort Hamilton High School in the Bay Ridge neighborhood of Brooklyn.

We tracked down two of her high school classmates to talk about what it was like growing up with her.

"A classic '60s liberal," said Charles Saydah, a retired journalist who served with Yellen on the school paper (Yellen was editor in chief), and also ran in the same social circles. "She has great faith in education as an answer to a lot of societal problems."

Susan Grosart, a retired school committee chair in Massachusetts, said she met Yellen in 7th grade when they were both "special progress" students, a program that let gifted youngsters breeze through junior high in two years.

[...]

Grosart recalls seeing Yellen after they'd completed their first semester at college— Yellen attended Pembroke, the then-women's section of Brown University — and she mentioned she'd taken an economics class.

"She was like, on fire," Grosart said.

"She just loved economics from the first minute she started studying it. She lectured me continually about different economic topics, and you could just tell she'd found her passion."