man i just wanna say hey first of all to all of u guys and i read all of ur posts and i agree with just about everything the was said
one thing inparticular that i agree with was said early on about jet li should NOT be goku and SHOULD be vegeta i always said that and its nice to have sumone agree with me
While Goku is 12 at the start of Dragonball, and I think (not sure) he is 18 when he defeats piccolo (doing the math, the martial arts tournament is every three years and he fights in one when he is 12, 15, and 18). And 5 years pass before DBZ (so he is 23 when DBZ starts), he trains a year before Vegeta comes (24), he doesn't come back from the Namek battle for 1 year (25), he trains 3 years to fight the androids (28), he goes in the hyperbolic time chamber for a year to fight cell(29), he comes back to fight Buu 7 years after (because Goten is 7 and trunks was just born before Goku died and he was 8) so now he is 36, after defeating Buu they have to wait 10 years for the next tournament so by the end of the Series Goku is 46 and Vegeta close to 50. As Vegeta says to Bulma, Saiyans retain their youth so they can fight longer. Just my take on how old they are.