and old age are emphatically not the same thing.
Old age does bring some changes to the way our minds function. We may tend to be tired more often, and there is some decline in ability to learn new things quickly. Memory also is slightly impaired. However, these changes that are normal with old age should not and do not impact overall social and cognitive functioning.
If you feel that your grandmother is having problems with memory that are impairing her ability to function in her normal everyday life or that pose a safety risk, then those are more likely to be signs of dementia. Dementia, unlike simple old age, causes major changes in memory and other areas of cognition. There may also be changes in personality.
If you are concerned, the first step would be to help your grandmother get in to see her primary care doctor
. They will be able to investigate all the potential causes of memory problems, including various medical conditions as well as dementia. They may want to perform some blood work or other tests to help with the diagnosis. If your grandmother does end up having dementia, her doctor will be able to help with a treatment plan.