Are dresses too formal for house parties?

I was recently invited to a house party for NYE by a new friend of mine. I'm excited to go as I've never been to a party at someone's house before (other than Bday parties as kids).

But, I'm super nervous about what I want to wear. I was planning on wearing a dress from Killstar (the Blood Rose mini) but my friend who I've known for awhile said that the dress would be "too much" and I need to tone it down for a house party, as people usually don't wear dresses to those.

So mg question is: are dresses too formal for house parties? And if so, what should I wear for a NYE party as someone who is a romantic goth without looking too "costumey" or out of place?