Are rebound girls a negative thing?

I think I was a rebound girl for my ex when we were together. I just found some stuff out and connected the dots and looked at the months. But we were together for a year and a half and had to break it off bc of long distance recently. I know it doesnt matter now.. but is it bad to be a rebound like that? I think we ended up pretty happy and well together throughout our relationship. And how close between a break up and seeing a new person is considered a rebound ?