I certainly have complete control over my physical actions at all times. The only exception is if I have a psychotic break. In that case, outside forces will eventually take responsibility for my physical choices. If I don't die first, that is.
The concept of impermanence had nothing to do with whether or not I will put alcohol into my body at any point in time in the future. Even if a changing circumstance in my life is so horrific, so deeply painful that my mind tells me I just cannot cope without drinking, then I still have made a conscious choice to drink alcohol.
I can say will full confidence that yes, life changes every minute of every day. The only constant is that I control my choices. Sometimes they are positive, sometimes not, but to suggest that my alcohol consumption is an unknown, at the whim of the impermanence of life and the non-existence of time, is well, for me, just plain inaccurate.