Never forget, the Internet is NOT private. The owner of a site, for example, has your password and can enter your account as easy as you can.
There are many people who know how to play others.
Here is a Facebook user; “Carla Smith Brown”. Pretty clear she was born Carla Smith, married Brown.
Do a Google.
You might find out that Carla Smith attended Erasmus High School from 1969 to 1972. You might get an image, you might get some information.
You look at the names of others who attended the same year, maybe were in the same class or club.
You can do a bit of a search on each to make sure they are still alive.
Then You can post; “Is this Carla who went to Erasmus? It’s me Linda!