Okay kiddo, so a colored school is a school that was made a long time ago, when people thought that some kids were better or worse than others just because of the color of their skin.
Back then, there were white schools where only white kids could go, and colored schools where only kids with darker skin could go. It wasn't fair, because everyone should be able to go to the same school and get the same education.
But eventually, some people spoke up and said that this was wrong, and they worked really hard to make sure that all schools were open to everyone, no matter what color their skin was. So now, we don't have colored schools anymore, because we believe that everyone should have the same opportunities to learn and grow.