Dress for a formal dinner!!!

This is my first time posting here, and I was a little bit nervous about it 😅

So I am going to a black tie (black tie doesn't necessarily mean black!) charity dinner, and I'm stuck between two dresses. I am 5'2, around 165, and I wear a size 14 in pants, but sometimes a 12 in dresses. My skin tone is medium, and I have black hair. Also, I need help choosing what color accessories and what type! Do I just need a necklace and earrings? Do I even need a necklace?

Thank you for your help!! ❤