Should I sell my Charlotte Moore Dress?

I have a gorgeous hot Pink & Pale Pink Charlotte Moore dress size 10, and have never worn it, I got it to get married in for something different but had two kids and now its too big & I still haven’t got married. I am still organising the wedding and now have changed my mind and want to go all White.
It retails at over $400 and I don’t really wanna let it go but need the money.
Should I sell it & How much do you think I will get for it?
Please help!!!