I think your statement necklace is pretty. You could wear almost any top with a knee-length or longer skirt and that necklace and some heels and look nice. I think the other suggestions here have been great. Otherwise this is kind of a last resort idea but I've done this twice while I was nursing. I wore what I wanted to the wedding and brought either a big shawl or nursing blanket. Then I took the baby and a chair to either the bathroom (I know, kinda gross) or an empty room, stripped off the top of my dress and covered my whole upper body with the shawl and nursed like that.