The Terrible 3's

Can somebody please tell me where my daughter went? My wonderful little angel has turned into a bratty teenager... We had our first parent conference yesterday about her behavior at school. So far, she's called a kid stupid, bossed people around, told someone she doesn't want to be their friend, and spit (yes, spit) at two kids. Everyone says, "She's 3!" I realize, but holy cow I never thought we would have so much behavior management on our hands... The teacher said she's very head strong and street smart, and that she understands what's going on and wants to be sure everyone does what they're supposed to... We love her teacher and know that we'll be working together, so I'm not losing any sleep over it, but our parenthood bliss has been flipped upside down.