Why do people think I'm so mean for saying this to her?

I'm 18. so my ex boyfriend was dating to a girl cause he's dating her and she believes in no sexual stuff before marriage and I had sex with him when was I 14, I lost my virginity to him. I was the first girl he did anything sexual with, he rimmed a guy before me but that's it. I wrote on her profile "don't feel special because his mouth was on my vagina haha so think about that every time you kiss him,how do I taste?" I wanted to ruin the relationship so I told her that we had sex. So anyway she got really insecure and flipped out. She was so mad because she wouldn't get to be his first. Was that wrong? he had his tongue in my vagina before and every time they kiss I think it's funny cause of where his mouth was and how she's getting my leftovers. I wanted to ruin it because she's annoying and he made me mad and no I'm not jealous I had a boyfriend after him so I have moved on. what do you think?