You are going to get a ton of; "no mirrors in entryway" but I love having a mirror in mine!

Personally, I'd change the frame to a silver. If you decide you don't like the look of the gold, spray paint works wonders. Find a silver metallic of some sort and have at it.

I'd hang art. A mirror looks best OVER some supporting console or chest. You have no room, and the door swings TO the mirror. It looks like a very heavy thing hanging in mid air .

Try art instead.

Your light appears to barely clear the door. A flush mount perhaps, better..

I like the gold and the gray, but I agree that the mirror isn't the best choice there. It looks like the door could hit it when it opens, and there's too much empty space below it. Have you considered hanging it vertically or somewhere else?

A mirror needs to reflect something worth seeing twice and that does not. A piece of art is what you need and it can be quite large since you have no space for a table there The pic Jan posted are the size of art you can do. I would change the light fixture to something more ceiling hugger in the space for sure.