I like the courage that you have and the maturity in your thought at your age. I didn’t have the courage like you in my school times. Don’t worry, with exposure, you will learn to not panic in those moments and with it, you will learn to manage stutter better. One advice I would give you is when you anticipate that you are gonna stutter on a word, try to not give that anticipation any importance. In my personal experience, the more importance i gave to my anticipation the more it became true. Face challenges and become stronger. Lots of strength and love to you!!!