Considering this should be korean age system, in the international one they would be either 25/26 based on the point of time and graduated school at 18 (20 in korean age system). Meaning the children were born when they were around 20 and conceived when they were 19.
Still childish for 25 year-olds, but I guess it's just his arrogant selfish character. I hope he falls harder hahaha
That age system was removed around years ago
It was officially abolished 2 years ago, yes, but it's still omnipresent in the culture and part of this work of fiction as it clearly mentions them graduating at 20, not 18 (c3 "having a kid at 22", one year for the pregnancy (21) and that kid being conceived one year after the slept together (right after graduating at 20 in korean age). Just because something is being officially abolished in state documents and so on that doesn't mean it gets abolished from the culture as well. That'll take some decades to fully get rid of
Ain't no way this is our MC. Bros fucking 27 and childish as helllll omg grow up and stop being a dickhead