Obviously we could be wrong about everybody's age except Kenta's, Osamu's, Takashi's and Akira's, and perhaps Ginga's. However, as I think was mentioned, a lot of anime characters have weird official ages since they look a lot older. And nothing can be done about that.
Dress Daidouji up in something other than a fancy suit, and I believe he could look younger ... Plus, since he is more or less of a main character, and that, in the past, none of the main Beyblade characters were as old as 17 or 18, it would be very odd to have a 'young adult' in the cast. From what I remember, the only character that was close to being important and that was 'old' was Takao's older brother Hitoshi.
Volkov was also a villain, and there were generally more adults in Bakuten Shoot Beyblade than in Metal Fight Beyblade. A few fifteen-year-olds also have deep voices; it is not impossible, my brother was just like that.
Dress Daidouji up in something other than a fancy suit, and I believe he could look younger ... Plus, since he is more or less of a main character, and that, in the past, none of the main Beyblade characters were as old as 17 or 18, it would be very odd to have a 'young adult' in the cast. From what I remember, the only character that was close to being important and that was 'old' was Takao's older brother Hitoshi.
Volkov was also a villain, and there were generally more adults in Bakuten Shoot Beyblade than in Metal Fight Beyblade. A few fifteen-year-olds also have deep voices; it is not impossible, my brother was just like that.