Kelso
In the manga Mamoru is only three years older than the inners and such, because when Usagi meets him he's in the 11th grade.
I said I had to look it up...since I am not good with all the ages...I had to look up Taiki's....and add on YEARS to the age it says...which was 16...16 a LONG time ago...being born in 1977...same age as Usagi and the others....
Usagi was starting...7th...8th grade in the beginning...because she didn't start Senior High School(Meaning High School) till SailorStars....making her 16...right? And Mamoru was leaving for college I believe...right? It depends on his age...18 or 19....I believe he was 19...
Ok! Figured it out...Mamoru WILL BE 31 this year....He was born in 1975..
ChibiUsa is alittle harder to figure out....Usagi was 21 when she had ChibiUsa...right? Ok...1977+21=1998....that is the year ChibiUsa was born it seems....making ChibiUsa as of today....8....but it depends on how Naoko has it...