I have a custom built off the long lifespan:
newborns- 5
Infants- 15
toddlers 20
Children 40
Preteen 40 /Teens 40 (Technically the Teen stage is 80 sim days, but half of that is the pre-teen trait/stage)
young adult 120
adult 125
elder 80
I don't mess with pregnancy, beyond pausing pregnancy for the families in my rotation *if* I care about naming the baby. I have a rotation where I play multiple families and so I like to be there when new babies are born but otherwise I do like my families aging/getting older and even being surprised by a birthday. But I don't want it to happen too fast and I found normal was too short for my rotation. It was fine when I had 4 familes, but now I have like 6-8 in various levels of roatation management. I like my kids to have grandparents. Grandparents are really useful for managing large households and I like large households, so I don't want grandparents dropping dead too fast.