Since I can't see the quilt, I will not say it is fine. It is obvious you feel you made a mistake so I do not speculate and say it is ok or your grandmother will be ok with it. It has been my experience over the years seeing 1000's of quilts that when the quilted corners do not match, then it is noticeable. Another point....it is pointless to suggest a solution to a problem like this if you can't see the problem.