First, you are still young so you have a lot of time to get over this. I was the same way and now am in a sales job where 99 percent of what I do is on the telephone. Guess what? I am now better at talking on the phone than in person. When you do it enough eventually a switch flips and you become more comfortable with stuttering. Your speech does not need to be perfect but the thoughts and ideas you are communicating is what is most important.