those are the ages of their respective games, not the characters themselves. the characters themselves are in their mid-20s. if you google "how old is mario" it will say 43, which is the age of the game donkey kong, released in 1981, and if you google "how old is peach", it will say 17, the age of the game super princess peach, released in 2005. if you google the same terms but say "the character" at the end, the results will give you a more accurate description. Super mario bros will be 40 years old next year, as it was released in 1985.