It's a really nice quilt for a first attempt; you're starting off well!
Are you going to quilt this "quiet" quilt on your own sewing machine? If so, I might suggest a "busy" backing fabric -- doesn't have to be "wild" just somewhat contrasting and printed -- as that will help hide any mistakes or less than perfect stitches (Who makes PERFECT stitches, anyway???).
And if you wanted to, you could piece your backing with different fabrics and virtually make this a two-sided quilt, examples of some piecing ideas below.
Jan in VA