Need to open up to somebody...

Hi- I'll make this short.

I'm 16 in 10th grade, and i'm kinda anti-social and shy. I'm not very open to people but I want to be, I just haven't had any courage to really make a conversation with anybody and I don't want to sound stupid when I do. It's the 3rd week of school and I still haven't talked to anybody what should I do and how?

Thank You:)