well if you want to work on calmness and relaxation i would encourage that. It can't do anything but help. I'd be curious to think about when you are confident and when you arent. is it based on the situation or the person youre speaking to? is it dependent on how worried you are about stuttering based on the topic/listener? Is the fear of not making a good first impression or not impressing someone (dad perhaps) making it more difficult? I guess at least for right now if you dont want to see an SLP could be to start up a meditation regimen or something and see how that goes.