while creating a new char you can define the age of him/her. but as far as i know this doesnt change anything in game. so the age can have some advantages and disadvantages like in the real life.
for instance an older age can bring more skill points per level (age brings experience thing), better barter or repair skills and maybe even charisma. but it will reduce the speed while travelling in map and the carry weight... and a younger age could raise carry weight and map speed, and maybe a better healing rate, better melee or unarmed demage but it will reduce sp/level and barter skills. i am not sure if the current engine supports this change but it would bring new features to game and make char creating more interesting.