I had a family that was aging fine. Then moved a grown child out to their own family and aging stoped for them and the original family members that are now neighbors. All age progression is on for family and neighbors. Not sure how to fix. Will age up with cake but age does not progress for them and want neighboring family to progress as well.
see here and maybe this cheat will work for you before you use the cheat save your game
ctrl+shift+c hold all 3 together in the menu bar that appears at the top of the screen type in testingcheatsenabled true hold down shift and click the sim you want to age up then click "Trigger Age Transition" WARNING once you've pressed the button you can't cancel the transition, and you can only age sims up - not back down again
go to the ...options in the settings menu then once in options go to gameplay uncheck the enable ageing option this will prevent all sims in your game from aging or If you would like to slow down aging rather than turn it off completely leave the enable aging box checked but use the sliders for the sims aging sliding the slider all the way to the right for an epic lifespan
