St. John silk dress gently used ( fits like small/ med 6/8) it’s a size 4

Beautiful silk St John dress. This can be worn year around. Black tights & sheer turtleneck for winter. I have this st John’s belt I wore a few times with it. Size 4, but I’m never a 4 in dresses . Fits like small- Med- 4/6 ? I bought from the REAL REAL. Bust 17 3/4. 💙🩵🖤 debated about selling .. just not wearing my dress up cloths these days:( color is true to first photo, not the ones I’m wearing ? Strange how that really changes in different light 💡