There's nothing wrong with the purple, but as ube quilting said, you want to consider whether you wish for your quilting to really show up on the back. I'm assuming you're going to quilt it in white. That being the case, I'd pick a lighter & busier print than the deep purple -- maybe either the purple check you used in the border or the medium purple floral print you used in the quilt top ... or any print that has one of your colors with white in it would really look nice & won't make the quilting stand out too much.
Of course, if you are having it professionally quilted or you are a fantastic FMQer, the dark purple is definitely the way to go to show off all the beautiful quilting.