HI everyone, I'm new to this board but not the Knot.

I'm getting married June 5th in Northern California. My bridesmaid dress in strapless and one of my sisters does not feel comfortable showing her arms so I got her a dressy cardigan from JCrew to wear with her dress. At first I thought well then all the bm will wear them since she is wearing one, but after talking to two of the other girls they don't want to wear them and that's fine. I just wonder if it will look weird that she might be the only one wearing a cardigan??
They are all wearing the same dress in purple so I figured who cares since I'd rather have them put their own personality and style into their ensemble since I don't want them to be tooooo matchy.