Is absent-mindedness different from early onset Alzheimer's?

I was just in the shower (I know, TMI) and I couldn’t remember if I had done the conditioner or just the shampoo. I know where my mind was – a million miles away. This kind of thing is not infrequent for me and I know my mother always worried about Alzheimer’s, even at my age. What do you think? Is this different from the early stages of dementia or a precursor?

I’m not asking anyone for a diagnosis, I’m not overly concerned yet but I think it is an interesting topic to discuss. Are some minds more prone to wander away from the practical world? Is this indicative of anything?