The first part is easy - you just need an interest in the general field. People with a passion and background in both art and computers have an advantage. However, there are many UI and UX designers who had neither - just the proper training.
You should think about which one appeals the most to you - User Interface or User Experience. Some people do both, but many specialize in just one.
It doesn’t necessarily require a degree, but it does take some schooling to become a UX or UI designer. There are a variety of training programs available, many of which can be completed online.