AIW for telling school staff this?

I told school staff that since im 18 they can no longer tell me what to do. I told everyone that the no phone rule doesn’t apply to me since im an adult. I’m grown. They told me that using my phone wasn’t allowed and I told them that i’m 18 which means i’m grown. Was I wrong for telling staff im grown?

They also told me to stop cussing but I told them that grown folks cuss and im grown.