I NEED HER TO THINK IT'S NOT ME SO I WON'T LOOK LIKE A FOOL (10 PTS)!!!!!!!!?

I needed a prom date so I started tlking to this sophomore guy who wanted to go at first. But later he changed his mind but I kept tlking to his sister on her blog trying to persuade him to go cause I really needed a date. They both thought I was creepy & I eventually went w/ friends but his sister is in my art class. Someone marked on her painting & she thought I did it, but I didn't. Then mine got marked on. Idt it was her; I think she had someone do it. But anyway that happened a while ago. Now she is running for class officer. Someone put on her blog how they put up posters for her & she said how that is creepy & she thinks it is me who said that. She put, "Anna, get off my a*s*s you crazy b*i**t**ch." I didn't even do anything. Now I want to write someone to fool her to make her think it isn't me (which it really isn't) before I look like a fool. What can I say to convince her it's not me? Thx!