knee length dress for a formal?

[poobumfartbollocks]

I have a formal to go to at the beginning of November.

I am ever so slightly broke and have a knee length chiffony silky strapless dress that I wore on a fancy night out last year.

Is knee length OK for a formal these days oh wise and wonderful ladies of style and beauty?

I believe so. I am going to a black tie dinner and dance in December, and I'm told that people wear short or long, about equally split.