The older or the younger sister? Younger would be about 40. I have seen her more than once at Target, but have not pulled the random "hi you probably don't remember me".I can trade you a card I got from one of your old sorority sisters. Made me feel really old since she must be 40 now and I have known her since she was 3 years old. Her little boy is pretty cute.
Speaking of the random meetings, I was leaving the mall and held the door for an older couple who looked familiar. After they walked out they stopped me and said, "Aren't you a (maiden name)?" I probably have not seen them in years, I think they go to my parent's church. My kids look so much like me that people from my hometown can place them in our family by looking at them.