Concerns about Dementia and Family History

I had a CT in April, my brain was fine, no white matter disease. August I have AN MRI I have mild to moderate white matter disease and mild atrophy. all drs have t9ld me I am over worried about it. but my mom, grandmom, 5 of grandmoms sister, my great aunts died of complications of dementia. most have been years of dementia before they passed away my great aunt Gladys died in a matter of 3 to 4 years. my great aunt Shirley also passed away quickly. mom, grandma and the other great aunts lived 13 to 14 years. the last 4 to 5 were terrible years. u fear I am going to pass away soon. I 65 years old l, already searching for words, very clumsy and walking with a cane, I do not retain appoinents I have to put it in my phone calendar and so does Ron so we do not forget.