I hear ya... when someone with one or two chihuahuas pass by and the dogs would go crazy on my Ace.. lunging and barking like nuts people wont react.. Now when Ace bark just once people look at him right away cause his bark is so deep.
I agree with everyone including yourself here.. get a real trainer. Good luck with your baby !! Mine is also 3.5 month.
Ace GSD BT/BB 3/12/2014