I personally think a lot of people talk to themselves and do so frequently and it is not a problem. Some live in a rich imaginary world and they talk out loud to themselves out of loneliness. It's a coping mechanism. And others just do it to self organize. Harmless any way around it. If "it" starts talking back and telling you to do things that are criminal or nefarious in nature? Okay, we'll get worried. But talking to yourself, pretty common. :>)
It may be normal for you. Lots of people do this. In fact, pretty much everyone does this in the sense we all have thoughts. So the question would be, does this bother you? Are you having anxiety about it? Are you doing this in a way that is new for you and is causing concern? In short, it's only a problem if it's a problem for you.
I think it is normal. Every senior I know does it!