>>56258735There are not any canonical ages given to those characters. The "10 years old thing" is anime only.
Therefore it's perfectly reasonable to imagine or interpret some protags to be 16-18, or even 20 years old. The only exceptions to this might be the gen 7 protags since the Island Challenge is intended to be a coming of age ceremony, but even then, there's no explicit age limit stated.
In addition, the male protagonist in Arceus grunts with a deeper voice, similar to adult Link. We can infer he is also somewhere around 18.
