Answer:
It boils down to birthdays
Step-by-step explanation:
If Today is August 10th, and Jin is 28 in korean age right now and his birthday is August 11th and Yoongi is 28 Korean age and his Birthday is August 13th, on august 11th, Jin will be 29 Korean age and 27 international, while Yoongis birthday is a day later, but same year