Am I being self centered?

This just happened. I normally cook dinner for my boys, myself and a friend that that lives in the basement. Because neither one of my boys are here, I told my friend I was not cooking dinner. No big deal right. I was kind of hungry so I grabbed a nice leafy green veggie and threw it in the microwave to cook. My friend comes up and says, “did you cook those veggies for you?”. I replied, “Yeah, you want some?” Well she proceeds to get upset with me hollering about me being self centered because I was only cooking the veggies for me. I said, “you ask me a question, I gave you an honest answer; what is the problem?” She rambles on about me not understanding, she said, “you just told me you were not cooking dinner and then I come up and you are cooking for yourself, You are so self centered” I am befuddled how me cooking veggies is such a mistake and self centered. Tell me was I wrong for not offering the veggies I cooked before she knew I was cooking them?