Make sure you remind her to always cover her body since at 10; she is now starting to grow. Due to her still childish mind and behavior, she may be finding the feeling of staying without clothes comfortable and good. With time, she will come to appreciate the importance of covering her body. It may also be important to take her to a clinic for check up on any skin condition that might cause resistance to clothes.
My nephew has a hard time keeping his clothes on, and this is what I do. Tell her that it is nice to have on clothes because they are very nice, and for little girls, they are pretty. Then ask her if she is going to keep her clothes on. If not, ask her why and persuade her to keep them on.