I think teens look fine. My bigger problem might be that (by default) they reach 29 before turning Young Adults. I find it a tad disturbing that a person aged 28 looks like s/he did at 16. That said, it's pretty easy (and sometimes even fun) to make a teen change from young teen to old teen somewhere half way through the life stage. I have a few routines taking care of that, and also giving them more responsibility at 22 and 25. Waiting till 29 to get married or to *start* University seems a bit off, though. But then - adulthood lasts forever :)