To me, as someone on the awkward cusp of young adulthood and normal adulthood, i tend to relate to highschool age characters by casting my memory back on myself of that age. Like, for example, i watched eva for the first time recently, and i kept seeing all the young characters as aspects of mayself or people i knew when i was younger. It's a deliberate mode change i shift into, putting the kid lenses on to see them as i one saw myself and others