Could this be Alzheimer?!

Could this be Alzheimer?

My mother, now 75, asked me the same thing (the date she was supposed to do something) 6 times, between today and two days ago. She has always been an extremely clever woman with a very good memory. But I have sensed some "fogginess" in the last year or so. Her reasoning has lost sharpness and logic.
Now this.
Is this just a natural result of ageing or should I be worried something like, say, Alzheimer may be setting in?

As a final note I must say that she has trouble walking (since she was young, totally unrelated to age) so seeing a doctor about this is not really easy. I wold just like to hear some general, "layman's opinion" first.

Thanks

I'm a medical Student and saw your question. I'm sorry because of your mom and hope that she become healthy. but all the signs show us Alzheimer.
but you should ask this question from a neurologist.
he/she will help you better.
thank.