The info on his age was found in some magazine, though we can't be sure if the info is correct because we don't know if the magazine was unofficial.
For example, I have an unofficial Tekken guide that says: Yoshimitsu is an 'alien' and that his rival Kunimitsu is his ex girlfriend. LOL! Now we all know this can't true, especially the alien part.
So we can never be sure about it unless one of us gets our hands on that mystery magazine.
Though, I wouldn't be surprised if he is this old. This could be why he likes to upgrade so much.