I think virtuoso means they live that long if they are adopted as adults at the very beginning or are chosen as a spouse. They are in their 20s at that time, so will live another 30-40 years until they die of old age in their late 50s or their 60s.
Children chosen to inherit, though, appear in the game from age 2, although they will usually disappear for a while while they are at college. Even if they inherit as a child they will automagically get older.
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To err is human; to arr is pirate.