....im confused. Are they in school? Older? Is it jumping back and forth?

This is part of a long flashback when they were in school. when the parents separated Jaegyung stayed with his mom and Dohyung went with the Dad. After a couple of years the mother leaves for the US and Jaegyung goes to live with his dad and Dohyung .

But there is jumping back and forth right? Cause it just feels weird like they go over everything twice once in school once as older?