what is the age gap bwtween jin and seho? It must be 7-8 years or more.

Can't be too many since they're both at uni together. Unless he's been there for a long time? Which I don't think he has

Said they met at 1st and 4th year meet and greet. So probably 3 years. But they've got that mandatory military service stuff I don't properly understand so maybe 5?