I would also not recommend FMQ on a real project until you have done many practice squares. Gloves help A LOT!!! pin securely or use a spray adhesive.
If I was going to stitch in the ditch, I would do that first. This will stablize the quilt and you may be able to remove a lot of the pins, if used. If you do this, you can start your FMQ anywhere (unless the center panel is really big). If you are just going to do FMQ on the whole thing, then I would start in the center and work your way out. It's up to you if you want the quilting to extend to the edge of the quilt and be partly covered by the binding or if you want to stop 1/2 to 1" from the edge. Personal preference.
Again, whatever you decide I would strongly recommend not to FMQ on a real top unless you have done some practice pieces.