At 21, Jon Jones has won an Iowa state high school wrestling championship, a National Junior College championship, holds a 5-0 MMA record and as far as I know is still the reigning Battle Cage Xtreme / USKBA 205lb. champion. He's been fighting professionally since April. Of this year.
He just signed a four-fight deal with the UFC, making him the youngest fighter under contract in the organization. And he's facing the also-undefeated Renzo Gracie-trained IFL product Andre Gusmao - on about a week's notice, replacing Tomasz Drwal - this Saturday in Minnesota. Check it: