How old is Himura Kenshin? In the anime, Kenshin appears to be about 17 (at least to my western, Caucasian eyes).  Consider that the revolution was 10 years in the past, and it must have taken years during the war for him to develop his skills and reputation as Battosai the Man-Slayer.  At a minimum, I think he's got to be 31, and that is if he got started in the revolution while still a mid-teen.
A simple google search returns the following:


  Age
  
  28 (about 33 end of series)


Source: http://kenshin.wikia.com/wiki/Himura_Kenshin