It is probably not the most accurate to be asking this question in PC, as Naminé sees this place as mostly a gathering of teenagers, even outside of the Pokemon section. In the Pokemon TCG tournaments, it's evident that there are some adults who are into the fad as well, although they're a rarity. The average age, as mentioned by Ms. Lily, are probably teenagers. Naminé guesses that those who love Pokemon beyond elementary will most likely stick to Pokemon for a very long time too. If they are not afraid of peer pressure of teasing due to liking Pokemon, then they probably really like it~