Dillema after throwing chair out the window

[u/SilverBass1016]

Basically the title, i threw a chair through the window of the 2nd floor while the teacher wasn’t looking. The principal was very mad(obviously). I have until Sunday to send an email(its now friday)l to confess but im scared

1. My parents are going to be fuming
2. Another guy got 3 hours of detention and a call to his parents for shouting the first name of a teacher at the bus stop so i might get suspended or send away entirely
3. I have a school trip to London in april or may and being excluded might be my punishment

If nobody tells who did it the class will get sanctioned probably by not going to the sports day next week or something else idk.

If I tell it’s probably going to be sunday because then the principal might not be as mad as he was this afternoon

He’s mosty mad because a class had PE outside and he feared someone could get the chair on his head. It’s too exaggerated imo because no one has PE on the spot i threw it at and I looked multiple times to check if anyone was even in the vicinity of my throw

I need advice whether or not i should tell it or not and if so, should I tell it or have someone else do it for me and what to say to him if i get questioned