I tend to start off with Young Adults or Adults with ageing off so they stay that way forever. I just get too attached. If children are born, I usually like them to remain with their parent/s as toddlers or children. However, I do have one vampire household where I plan for their daughter to reach young adulthood and have a child of her own before her father turns her into a vampire. The grandson will want to break away from his evil vampire mob family though and be a 'good vampire', so he may have children that reach the elder stage, as long as they don't decide to join their infamous great grandfather of course. I do feel this will be really fun to play out and it will be nice to see my sims grow and the different journeys they take.
I also have one main household/save that I'm very attached to and have been playing since I started with TS4. The couple now have a toddler (aged up from baby) and I do plan on eventually ageing her up to a child, although I want to enjoy the toddler stage a while longer. She will likely remain an eternal child for her vampire daddy though since I plan for her to die and return as a ghost, which will be a first for me. That's the thing when you play occults - life doesn't end with death!
