Convince parents to go to midnight showing?

Hey Yahoo! Community!!
So i just scored some AWESOME midnight showing tickets for HP7! :D :D
my friend is gonna be gone so she is selling them to me and i have two
so i asked my friend AMY to go :))
So idk if my parents will be okay with it. How can I get my parents to
let me go!?

Thanks to everyone who answers! :)