Han Daesung's "Oppa" vs "Hyung" distinction is confusing me here. From all of the other Korean manhwa and novels I've consumed, I had gathered that they're both terms of a kinship/respect for a slightly older male ("older brother"), but that which one you use depends on the sex/gender of the speaker. So asking someone to switch between them is asking them to change their sex/gender identity. Is that something you can casually ask someone to do?
Or have I misunderstood something about that kid and that "she" has actually been a "he" this whole time, and Han is trying to say he's tired of it? Because the censoring in earlier chapters definitely seem to imply that the character is a "she", and all of the other pronouns say "she"...