Can a teenager use Selione?

No. Selione is for adults, eighteen and over. When you first meet Iphthimé she asks when you were born, before your name: the date is read once, on your own calendar day, and never written anywhere — we keep only that you were old enough. If the date is not an adult's, the account closes on the spot, nothing typed is kept, and it is erased within thirty days. A declared date is a declaration, not a verification: we check no document and identify nobody. An Echo is built from a whole life, and a sixteen-year-old's has its first chapters still to live.