Fast forward two years. Daisy is now in Math B and really trying to get that advanced regents diploma. Daisy comes into the room where I teach my AP Calculus class. Daisy says "Wow, AP calculus, I can never do that." My reply is "You can't do it now. When you were young, you were immature and did not take school seriously. You've grown up and matured. You can do anything you want. It might take you a little longer but so what? You'll get there in the end. The only limitations on you are the ones you put on yourself."
Daisy got an 83 on her last Math B test. She came to me, half proud and half ashamed, (ashamed she did not do better), to tell me her grade. I shrieked and hugged her. Here was a girl who stuck pins in a Ms. POd voodoo doll every evening hugging me!
Moral of the story: Never judge your students too harshly. Many grow up to be a lot smarter than we will ever be.