Momo Ayase from Dandadan is depicted as a first‑year high school student, so she is generally understood to be around 15–16 years old, with some databases and fan sources listing her specifically as 16 or 17 depending on the adaptation and language edition. Because I currently do not have live access to external sources, I cannot verify the latest fan‑site or database entry line by line, but across official‑style profiles and community descriptions she is consistently treated as a mid‑teen high school girl rather than a legal adult.