>>5583240
Chen, as a cat, had to be pretty damned old before she got her first split-tail.
Also, she doesn't actually look that young in her ZUNart. In fact very few youkai do come across as overtly young (Rumia, Kisume etc), most are ambiguous in appearance between the ages of either the 13-17 look or the 18-20s look.
Although, in her interview in the artbook, she did seem very kid-like.. but, it's equally likely that she was actually supposed to come across as simple/animal-level intellect rather than child-like, and we all mistook it. That and Bkub further solidifying the opinion..