Any other step moms feel awkward?

I hate the word step mom and step son. My daughters never call the oldest their half-brother and for good reason. I strongly believe in all of us just treating each other like family. But I feel obligated to use the word "step" when talking about him because his mother is still a huge part in his life and a huge part in mine, we all get along so well. So I would hate to claim her obvious position. Also I am far too young to have a 6 year old and if I ever called him my son it would definitely come up in conversation. (I am only 21).