I was also very introverted when I was in primary and secondary schools, and I didn't even dare to speak in public. Answering questions in class was called up by the teacher for more than three minutes, and tears were almost falling. Later, my classmates told me that every time I was nervous, I could express my thoughts, and no one would say anything about you.
Then I tried, starting with a new environment. For example, outside the cram school, where no one knows me, I try to chat with my classmates after class and answer questions actively in class. The teacher also praised me and gave me confidence. Later, I exercised bit by bit. In high school, it was a new environment, so I continued to practice. . .
Now I am not unassuming, but I should not be introverted.
I think you can try, if you are determined to change. . .
Finally, a word for you: Go your own way and let others talk!