jf – I disagree. (unless you say, “Oh, I can’t believe you’re so-and-so, I live two doors east of you”)
There are people who I have figured out because they gave info that only would mean something to someone who was there, and I was there. You have mentioned enough info for me to assume I might have known your grandparents but I still don’t know who you are, and I don’t think finding out would tell me who your friends are.