Lifespan

I do things a little differently, I have it set to normal lifespan but only age when household is active, I prefer this way as my sims wont age without me and if I want them too have extra time on a life stage I will get them too drink the potion of youth or have a evil sim with a couple of cowplants lol, the townies in my world (unplayed sims) aging is off because theres no story progression the townies just age and die without doing anything at all, I age them by cake on my sims birthday if they are friends or lovers of my sims, the only true immortals however in my game are really vampires ?