JoAnn, my younger sister had the same name. She was born with a severe heart defect. But you would never know it. She was on the go every single day she was able to be. Her mind was as sharp as can be. Had she lived, I think she would have outsmarted all of us.
Having said this, I too would like to add that you are on the right track. Keep that mind alert at all times. Every week when I go for my checkups, I have to go through a very large room filled with dementia patients. I have to give the staff a lot of credit. They work very hard to keep these folks involved in the world around them. The first thing they do at nine o'clock sharp is turn to their left and then to their right and introduce themselves to their neighbors. They have sing-a-longs, exercises, and all sorts of activities that require them to use their minds.
You are so on the right track. I wouldn't worry too much about developing dementia. You are going to be smart as a tack well into your 90's. Just because you look like your grandmother, has no bearing on your mind. You are doing all right things. You are staying involved in life and the living. Enjoy all those grandchildren and great grandchildren. Past studies have shown that when the elderly are surrounded by young people, their own minds stay alert and involved. You go girl!!!