This is such a cool topic because it is true that norms are so variable from one family or group to the next that it's useless to try to settle on a single norm for teens. @MoonlightGraham I come from an extremely male-heavy family (each generation produces almost nothing but boys, it's weird) and the guys at least, have things like losing baby teeth a couple of years earlier than other people's kids, starting pubertal changes at 7 or 8, getting wisdom teeth in the early to mid teens instead of late teens or early 20s, and being 5'10" at 14, is normal for us.
I looked 17 at 14, and by 17 almost never got carded.
So that first pic doesn't look anything like a teen to me, more like a young-faced 8 year old. I also wonder if it's photoshopped because of the way the lower face doesn't match the neck, but that's irrelevant.
Another thing of note, is that if we're being realistic, girls start out taller on average than boys their same age, in the tweens to early teens, because girls start and finish their growth younger, and are usually at adult height by around 16, whereas boys continue growing and gaining height between 19 and 24.
But the game makes things simple by making all genders the same height at the same age. So is it more realistic to say that "teens" should look like 13-14 year olds (which in both boys and girls is usually shorter than adults), or make them all look 16-18, in which case, girls are already at the adult height of women, and boys are already taller than most adult women and either as tall as most adult men, or in some cases taller?
I figure since 13-14 is just 2 of the teen years, but 15-19 is 5 of them, having them appear more as 15-19 year olds is more realistic and that's what the Sims4 teens look like to my eye but again, I'm not used to thinking of teens as looking or acting like children.