Your quilting is wonderful, your fabrics are wonderful, you did a great job.
I would add one thing. Put the black bias tape between the border and the main part of the quilt. Create squares in the corner making the black go from edge to edge. This will make it look like a real stained glass window.
You already have the black binding which would replicate the zinc frame.
It is wonderful as it is, but if you are going for the look of a real glass piece, add the extra leading lines. I have done this by just ripping out enough of the binding to tuck my black bias under the binding.