Great dress but runs large

I purchased this dress in two sizes , a medium first than found the Xsmall at another store. The dress is very elegant but has a generous amount of stretch, so I'll suggest doing down two sizes, especially if you want that flattering silhouette. It's not a body con nor is it lined. For reference I'm 5'6", 190lbs, bra size 36DD, and I have long arms and even wide shoulders. I'm keeping the Xsmall. As for washing I haven't washed it yet but I would recommend washing by hand, or dry cleaners, and avoid the dryer on hot settings.