No problem! This was just an algorithm, and it sometimes doesn't work 100%. If you can learn to draw directly in Inkscape, it would be a ton better.
In short, if you want to do this to your other arts, use the "Trace Bitmap" feature under the Paths menu. Use the Multiple Scans > Colors option and set it to the exact number of colors in the image, and turn OFF smoothing (it blurs things). Can take a lot of trial and error, so just play with it and watch/read lots of tutorials!