Is NOBODY wrong in the post ? POST : My niece (12f) and I (17f) exchange notes and drawings a lot (we live in the same house). Anyway, she made me a necklace, which I thought was really cool, and I wrote her a note saying how fucking awesome it was. 
Well, her mom (my sister) went into my niece's room without knocking (my niece was in the room), and read the note without my niece's permission. 

She is super pissed at me for writing my niece a note that contained the f bomb, and told me so, and that I should never swear/write words like that to/around my niece again (not that I swear a lot anyway). 

I thought it was completely unjustified, as it was a PRIVATE note to my niece, and none of her mom's business. 

TL;DR wrote a note to my niece that contained the word "fucking", and her mom read it and got pissed at me about writing it. 

So, Reddit, Am I The Asshole?? 