Being born in a Sunni family does not autmatically make you an expert in it either. For whatever reason you are not Sunni now that is your choice, but please divulge some reasons why you became Shia so we can all share. I mean what specific beliefs about Sunnis made you replace them with the specific beleifs of the Shi’a ???
I would like to know for educational purposes please. Based on what you have heard about the Shia by the Sunnis then the same ghalat fehmi exists in the reverse direction also. Some people from both sides do takfir on each other.