This is an extremely simple mod that performs a single, specific function -- it AUTOMATICALLY ages up all (non-played) babies, toddlers, and children to teens.   There IS NO UNDO button, so you need to be 100% certain this is the playstyle you want to have on ALL games.   Once you put this mod into your /mods folder, all new and loaded games will have all of their children automatically aged up.    Note - when you create a new game, you'll see children in the world