Im thinking about getting blonde highlights and then black underneath..?[cont.]?

No, I don't think you would look good. Highlights never look good unless they're less than 3 shades lighter than the natural hair color. The look personally reminds me of Christina Aguilera about 5 years ago when she was in her "Stripped" CD phase. It looks like a zebra. Your roots are the first thing that's going to show after about a week or two. So you will have blonde highlights, brown roots, and black underneath. Not a good look. How about carmel, honey, or red highlights instead? That would brighten up your face.