The dress is pretty, but due to the floral pattern, which makes it a bit busy, I'd stay away from floral shoes and would instead choose simple, coordinated accessories.
The neckline is quite high, so I don't know about a necklace. I would perhaps choose a pink pearl bracelet and matching earrings. Pearls are classic jewelry for daytime, and I think a pale pink would go nicely with both the dress and your grey shoes.
Do you have a matching grey handbag? Preferably something small and made out of good quality leather. A clutch bag or even a vintage style would look really nice.
If it's a formal daytime event, I would also wear a hat or fascinator. The style is entirely up to you. If it's an outdoor event, you could wear something larger and more dramatic, and something smaller for indoors.
Also, are you going to wear some kind of coat? I don't know when your event takes place, but I always need a coat/jacket/shawl, etc. unless it's more than 20C outside. Even then it can be chilly if you just sit.