Just thinking about the creatures who have an average lifespan of 40 years and how long it usually takes to master magic...Would that mean short lived Janah are at the disadvantage in mastering being Sir'Hibas?
Dying at 40 seems like it would get in the way of mastering any skill that takes a life time to master, magical or otherwise.
With respect to the rules of the game, a Janah with a shorter life span is at no disadvantage with respect to becoming a master of an art, magic or martial, however they would not have as long to enjoy wearing the mantle of master as one of those who live longer lives. The differences in lifespans might be shown in fictional aspects of the game by those with shorter lifespans being more driven to accomplish their life goals, they might also require slightly less sleep, causing them to be viewed as hectic or frenzied to those capable of approaching the task of becoming a master at a more leisurely pace due to the benefits of a longer life. In contrast those with shorter lives might view the pace of those with longer lives to be some what lackadaisical in its approach to doing and seeing all they can within the space of the the turnings of the suns which has been granted to each of the children of the Devah by the blessing of the Great Mother and Father.