Welcome from the UK. I would not cut the binding at the beginning. Just join the top pieces together , you may feel as if you want to be creative and add another border etc and make the requirement for binding more. I can never stick to a pattern. Also your 1/4 inch seam may vary and sizes change. I also leave the backing until top finished.
Enjoy your first quilt and don't forget to let us see a photo, we all remember our first quilt with a wide smile on our faces.