I have a height slider in game, I just keep forgetting to actually use it. I also think, since I play in rotation, and the last two house I played only has little kids, it just slipped my mind.
But I do try to make my teens look young as best as I can, and once they start to become older teens, I'll switch up their clothing choices.
Jayden just turned into a teen.
https://i.imgur.com/6o8fVQZ.png
It's not the best pic because he got struck by lightening, but I have (I forgot his name) is a sports jersey. I tend to let teens where that style.
https://i.imgur.com/tNUSaw5.png
Here his older sister, Amanda, has more "adult" taste in fashion. She'll be a young adult soon.
https://i.imgur.com/J3Ajcww.png
