Young adul life stage: the crusial moment of keeping or leaving.
I think, but who am I, you may want to keep your kids. As how far I am aware of your playstyle I do believe you don't want for Story Progression to take over the stuff and therefore you want them to live at home, parent home that is.
I don't have to ad anything new to this while everything I agree with has already said in posts above me but maybe you've seen the comedy: The 40 Year Old Virgin? Sims living at there parents home until the parents will move to the other side of the grass are not standard weirdos, so there is no related thing to be aware of.
Actually, I do this all the time ingame with multigeneration families.