My townies are mostly CAS made or generated, so the usual ways to tell them apart don't work. :/
I am simply going to send them all to college and then make them dormies I think.
That does make it a lot harder. I can usually tell when my townies are teens because I made them all and didn't make a whole lot of them, but I'm sure in a few months and after a few more generations are born I'm going to have no idea who's a teen and who isn't anymore, unless the townie has an adult-only hairstyle.