How tall is your daughter? I'm 5'7", so not super tall, but I find my 72" throw slightly too short for couch napping. When I make myself a couch quilt, it will be at least 76". Based on this, I think you need to find more fabric for another border.
Totally unrelated, but I also encourage you to put a pocket on it, like a quillow, for tucking one's feet into.
Your quilt is really pretty - I'm sure that whatever you decide, your daughter will love it!