Why is my cat scooting her along my carpet?

She is under a year old and weighs the normal weight for her size, she has never done this before and I never took her to the vet yet to see any problems. Her mother (My other cat) is perfectly healthy and never done such a thing. I thought it was cause she was dirty so I gave her a bath, but she continued to do it! :( Could this be a "red flag"? Should I take her to the vet? I need help!