Depending on where you're from, the saying "age ain't nothing but a number" might ring true. But in Korea, it's a BIG number. Knowing someone's age will instantly let people know where they stand on the super hierarchical Korean respect scale. Instantly, they'll know how to act, how to speak and how to listen.
There's something called Korean age, which basically adds one or two more years to your age (like we need it!). A lot of people have a hard time calculating their Korean age, but it's easy, yo. Check out this video for a super simple Korean age calculator formula :)