i might be wrong bcs i already forget most of the old story, but i don't think there is college in demon world(?) so maybe they can become a teacher right after they graduate or have the rank to be a teacher
supposedly iruma is 15, ameri is 17 or 18 most, then the teacher was like 24 or more. i think it's an average age for a teacher
Idk about your country but most of asian countries (including Japan and mine) just need to finish bacholers degree and get teaching certification to be a teacher, so even a 21-22 year old could be a teacher already. And this is a fictional world so maybe they don't even have university hahaha kalego could've been working as a teacher straight after graduation for all we know

So I thought ameri was only meant to be like 1-2 years older than the rest of the main cast but this is showing that she was born when all the teachers were like 6-7 years old? essentially when they were all still kids. Meaning that she’s closer in age to the teachers than the students? yet she’s still only about 1-2 years ahead of the main cast in the school system?
I know Ameri calls her self a “big girl” but i thought that was literally describing the fact that she is bigger than most demons, especially iruma, not her ACTUAL age.
I’m sure the author will talk about how exactly ameri’s blood works and how exactly NO ONE on the previously 13 crowns spilled the beans on her origins (I suspect mind-control/ mass-amnesia caused by sullivan). It seems to not fit in great with the current storyline where the bad guys are going after iruma because he’s human, imagine what they could do with a half-human!
I’m so confused