Chichi

Chichi is the daughter of Gyumaou.  She was a little scatter-brained as a child. And has quite a temper.  Trained by her father (who was trained by Kamesennin) she's an accomplished martial artist and one of the strongest on the planet.  She asked Goku to marry her when they were twelve.  He agreed, but had no idea what he was agreeing to.  When he didn't come back, she went after him, and fought him at the 23rd Tenkaichi Budokai.  At the end of DB she and Goku went off to get married. She was the same age as Goku, 18.