I don't understand why people marry so young. The small villages make obvious psychological sense, and since people are immortal you want marriage to be permanent otherwise you'd be drowning in exes. That could be done with having the Eternal True Love form at the first hint of a crush, or in purely arranged pairs (by O, or by people who decide they'd be a good match then ask O to make then soulmates), but for some reason you want people to date around and fall in temporary love. (The part of me that likes the eternal monogamous bond dislikes the premarital sex.) Given that, why not have people date casually until they're 25 or so, then slowly settle down and marry in their early thirties? If nothing else, it would spare O the headache of preventing people from growing apart when they become adults.