Over thinking about thiss?

Lets say i have a friend mary.. mary has a brother, say sam.. whenever i and mary met, she used to send snaps of us together to sam teasing us together and he would always reply saying i was pretty or complimented me..
Recently at Mary's friends marriage, i saw him and we both smiled at each other, i said hi just passing by.. now after 2 weeks after that, he sent me a friend request on Facebook, which i accepted.. but he hasn't sent a message and neither have i initiated a conversation..
Mary had come over to my home and send a snap of me (doing silly things to tease) and he sent me a snap request too..
I don't know why i am obsessed with the thought of him.. what do you think he is trying to do? I get a hint that he likes me but why hasn't he talked yet? even i haven't, I'm too nervous.. is he just playing or what?
Over thinking about thiss?
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