i wish it was, like easy for me to explain lol but the jp school age requirement is that you have to turn a certain age within that school year. so since school starts in april and runs until march the next year, when hitoya and jakurai were seniors, they would have needed to turn 18 within that period

so!!!! jakurai could not have turned 18 the january before the school year because he’d basically age out his grade by the time his bday rolls around again which means hitoya is technically older than jakurai since his birthday comes first in the school year lol