That is a great first quilt! Congrats. I like the layout and the colors. If you pull some of the peach into the border, that will help tie it all together. maybe a thin peach border then a larger outer border of one of the other fabrics you like.
I generally prefer a cotton blend batting. But if you are in a warm climate or you are aghast at the price of batting, a layer of flannel will work well in its place instead.