Hmm do you have pix? Sounds like a size 5.5 with beads might be better. Especially if you wash a lot and need to dry the ring properly. Also there is no harm in keeping it and returning it after the wedding if it's within return window.
I went diwn too far in size to come back up again. I have milligrain in the edge of my ring. When I puff and took off my ring it cut my knuckle. My knuckle is about half size bigger than my actual finger which sounds like you might be too. Also how is the weather where you are? If it's cold/raining I'd stay with 5.5 because there is a higher chance it will swell wen it's warm. When I'm cold my finger drops to maybe a 4.25 and is loose. I wouldn't commit to a full eternity either until I'm sure of sizes.
I went diwn too far in size to come back up again. I have milligrain in the edge of my ring. When I puff and took off my ring it cut my knuckle. My knuckle is about half size bigger than my actual finger which sounds like you might be too. Also how is the weather where you are? If it's cold/raining I'd stay with 5.5 because there is a higher chance it will swell wen it's warm. When I'm cold my finger drops to maybe a 4.25 and is loose. I wouldn't commit to a full eternity either until I'm sure of sizes.