I sandwich, baste, quilt, and then decide if I am going to trim it up. Quilting can change the dimensions of the quilt, as it does make it pucker/draw up a little.
If it is that close, I am not sure that I would trim... unless it really bothers you. I would personally call it close enough. Who knows? Maybe after quilting it will turn out to be perfect? :wink: :D:D:D