I don't know. I couldn't even get my sims to age to YA with that hack in. They'd go straight to adult. Sending them to college turned them into young adults just fine.
I ended up going to a backup I made pre-pets, playing without the hack long enough to get some kittens and puppies, then exited the game and put that hack back in. My YAs MUST live in Pleasantville, lol.
The only thing I would recommend is to avoid moving any existing YAs into the home neighborhood, because they WILL transform into adults.
My way was very roundabout, but I now have my YAs at home, I have a bunch of kittens and puppies (who, of course, will not age
, but that's fine with me since I also play with aging off), and my game is pretty much the way it was pre-pets, now.