Ohhhhh... "Fight the devil and you will make him stronger, ignore him and he will dissapear" Don't pay attention if you are uncomfortable... but age doesn't have anything to do with being weird, trust me ! =D Good Luck !

Why the old people adding the young people ? Because, the old people were requested by the young people.

Your question has two topics. "The old people that have added me are weird and ask questions about me and stuff actually". You can delete them from your friends list.

just to keep communication between different generations and to benfite young people from their experience.

As Wozitoya said they request to be added also it is not a bad thing to add a younger person , is it ?!