Hello Franz, I'm 22 and have stuttered for most of my life. Also, there's nothing wrong with stuttering so you shouldn't feel ashamed. Is it possible that you might have some form of social anxiety that triggers your stutter? I would encourage you to talk to your parents about your stutter and what you're experiencing because of it. They may be able to support you in some way. Youtube has lots of exercises and information on stuttering, so I recommend looking on there.