Been stuttering my whole life myself and im now 22 years old. To make it better at the age of 15 was maby for me the "top point" of how much i cared about my stuttering. After that you just seem to care less and less, but yeah its some tough years. I find it really hard on you the way people treat you, where i come from (Norway) most people have a very supporting view of stuttering and even bringing it up seems to be looked down on. Although i dont know how your culture is, i think its important that you say to all your close ones and make them understand thats its not something you can understand and stress makes it a lot worse. Look for some counceler in your school that have some authority over how your teachers treat you. Other than that i can only repeat that it only gets better from now on, you develop as a person and get less and less stressed out when talking to others, as more adults treat stuttering as its suppost to be treated. Keep in there bro