Mean Girls....

Have you ever watched the movie Mean Girls? I swear some days, I live it. Individually, I enjoy almost every one of my young ladies. However, when they get together, they sometimes just floor me. Today, I was in a classroom filled mostly with girls including one new girl. She seems pleasant enough, but is not dressed well and almost has a pathetic look to her. As her teacher, I have gone out of my way to make her feel welcome and to place her with young ladies that I know would be nice. Today, many of the girls began just talking about her like she wasn't there. They were saying how they didn't like her, she was not pretty, etc......etc..... I of course put an immediate stop to it, but the damage gets done so quickly and what did the new girl do?? Nothing, she didn't defend herself, she didn't cry, she just sat looking at her desk for the rest of the period. I kept her after and chatted with her, but I know it had to be a terrible moment for her. It was such a short time, but I bet she carried it with her all day long. I am not sure what else I could have done without making it worse for her later....besides putting a stop to it, disciplining the other girls, and giving her some girls that would be kind, it is so hard with high school age kids...what would you have done??