Would I have to pay to use these?

I want to do a presentation at school on "The Day The Music Died" a.k.a the plane crash that killed Buddy Holly, Richie Valens, and The BIg Bopper. I would likely play "That'll Be The Day" "La Bamba" "Chantilly Lace" and possibly "American Pie" If I am showing it for free, would I have to pay to use the songs? (Note: as I am a minor it would likely be the principal or school getting sued) Would I get sued or do I not have to worry about it? If I charged admission, would I have to pay?