When I was in school (I’m 27 now) I felt the way you do. I tried so hard to hide my stutter, avoiding presentations and never answering questions in class. I eventually had my parents get me a 504, which is a legal document that requires school staff to provide accommodations or support in the classroom. My plan said that I was not to be randomly called on or required to give presentations in front of the class unless I initiated it. At first, my parents thought I was trying to get out of things but really I was so anxious about speaking that it was have an effect on my education. My tip is to learn about stuttering and maybe give your teachers some information about it. Most teachers want you to succeed but since stuttering is not that prevalent, they may not know how to help.