No, don't change it. Right now the shirt is so unimportant, it very effectively enhances her features and the beauty of the drawing. I certainly didn't notice that it was ugly. I see only an interesting woman, beautifully depicted.
Great drawing again Jimmie. I think in addition to knowing how to handle a pencil, your concept of what makes a good composition is a great talent that you posses. This is what sets you apart. This one is one of your better compositions.