What to wear to a charity ball?

[Heyitsmeeee]

I am going to my first ever charity ball and really struggling with what to wear. Don't want to stand out for the wrong reasons 🫣. I am plus size 18/20 and average height. Are long dresses the done thing? Or would something sparkly like this be acceptable?
Thank you

Or this maybe?

I think either of those are absolutely fine, especially if you add posh shoes/bag.
My personal favourite is the first one!

is it black tie, cocktail, or lounge suits dress code??
If it's black tie then traditionally it would long dresses for women but these days cocktail length tends to be ok too unless it's something very formal. I think either of those are fine, I'm not sure the first one would be particularly flattering though.

Is it an annual event? Are there photos of previous years?

Or possibly a similar event at the same venue or involving some of the same people?