(fallen london stamps by I sometimes wonder if this makes me a wee bit of a jerk, but whenever I encounter, say, a bodily 15-year-old system with headmates who are internally 30 years old, I'm just inwardly like, okay, but I'm going to treat you as 15 years old anyway. (In contrast to the other way around - if I meet a bodily 30-year-old system with internally 15-year-old headmates, I'll still hold their system as a whole to the standards I would hold any 30-year-old, but I'll interact with those individual 15-year-old headmates as I would interact with any other 15-year-old.)
I say "sometimes" because it's not actually something I feel guilty about, in the end. My policy for how I treat teens is "like adults, but with more patience, with a bit more interpersonal distance, and without discussing topics I consider Adults Only." (That includes obvious Adults Only stuff like hornyposting, but also means like... I will not turn to a teenager for help with my interpersonal troubles, for example. It simply doesn't feel appropriate.) It's a matter of decorum, not hierarchy.
