Is it normal that i can actually have a conversation with myself?

Every so often, I'd walk in front of the mirror and comment on how I look today. then out of nowhere I'd start to critize myself, then defend myself, then back up my critize again, then defend again, and this keeps going on until the me who felt like b!tching at myself or the me that told me that I looked good would shut up and admit defeat. The same thing happens when I try to decide on something. I don't do this intentionally, it's kind of like I'm a different person, I cant really control what I'm saying, my mouth just runs on it's own. Is this normal?