Hi Zainab,
I was the “quiet and serious one” in high school as well. First off, there’s nothing wrong with that. Sometimes people don’t know how to react around people who are quiet and serious which makes them uncomfortable, leading them to say rude things. That said, you are not just the “the quiet and serious one”. You are so much more than that. I’m sure in your life you have been funny, loud,… We are so much more than a label. Perhaps to gain more confidence do something you haven’t done before like you said go to a dance, do debates…but do them because YOU want to; not because of the pressure of others doing it. I hope this helps:)