First ranked games, Matchmaking

So I don't know how this works, but judging solely based on logic, this shouldnt be logical. Im placed only in gold games for my promos and lose one game and get placed in bronze 3. Now every game ive been playing with or vsing only golds yet in bronze. And 2/5 teammates play the same as an ARAM bot at 3 AM. May someone explain this situation.