Confidence matters, even a lot depending on the person. But I think that speech therapist does not have any idea about stuttering. Stuttering psychological? Nah, maybe after a very big sudden trauma like the people who goes mute, but I doubt the root cause can be an hostile environment at home. I bet that if you ask your family and they are honest with you, some member, likely male, also stutters or stuttered when he was young and you inherited it