im in seach of a light jacket/coverup to wear to an xmas party on Friday. Im wearing this dress www.collectiflondon.com/en/Collectif-Mainline-Trixie-Glitter-Star-Velvet-Pencil-Dress/m-5596.aspx but in a wine/burgundy colour and have a coat to wear to travel. so I only need a light bit of warmth in case the rooms are cold. 21 and size 12?