When I was growing up, most of my closest friends were probably closer to my mom's age, and I've had work colleagues a decade or so my senior with whom I was most comfortable. There are people who are just "born older" so-to-speak. Or rather born ageless, in that they comfortably interact at a certain level with anyone regardless of age. Being interested in current events and "heavy" subjects much earlier in life than the average person, and just are more sensible. I think you see that in Elinor in S&S as well. And also Anne Eliot in Persuasion. And perhaps that's why I like those characters best.