This is lovely! It would make a gorgeous bookmark & I love how you've drawn & colored it. The color scheme works really well. And I thoroughly understand about the need to watermark. Personally I think they ruin a good picture image but I've been forced to watermark my stuff too so I totally understand.
I absolutely adore the colors on this. The oyster with the glowing pearl was a nice addition, especially with all her pearl jewelry. I really hope you do make this into a series!