I think they each chose whatever age they want to as my mom is 54 and still needs permission from her younger brother (she is divorced) to travel, and still has to travel with a paper giving her permission from said younger brother.
Creo que eligen la edad que quieren ya que mi madre tiene 54 años y sigue requiriendo el permiso de su hermano menor (está divorciada) para viajar y sigue teniendo que viajar con un papel en el que dicho hermano le concede tal permiso.