Shania Twain isn’t afraid of getting older! The pop icon, 58, revealed she fully intends to let her hair go gray and even has a plan to make the process a bit more enjoyable. “I’m embracing aging. I’m fine with it. I don’t have a choice; I can’t change it. So, I decided that whatever I can’t change, I need to have fun with. Going gray is one of those things,” Twain explained in a recent interview. “Of course, I can color my hair.” The “Up!” vocalist has experimented with her look and hair color over the years with wigs, which led her to a genius idea of what she wants to do when she fully goes…