I have had a pair of so-called excellent cut diamond earrings next to a pair that wasn't and both pairs sparkled the same to me and my husband. The only difference was in the price of the branded cut earrings. Personally, I think people overstate the importance of a cut grading in many, many cases. Believe me if the ring wasn't well cut you would know it! And frankly I have some old european cut diamond earrings that are gorgeous! What are they graded? I have no idea.
Trust your eyes, enjoy your ring. Not everyone has a Tiffany ring or a fiance who would buy them something like that.