I would certainly not allow screaming, I don't allow it here ever. Of course crying and feeling sad are ok, usually I will separate them from the group when they are like that, but if they start to actually SCREAM, they start to suffer consequences. She is old enough to know better. I'm not sure I would have a "talk" with her either. I had one who was like this right around the same age and honestly over time I would let her pout in a corner when she first came in and then when she was ready she would join the rest of us. I tried the whole talking thing but it just didn't get us anywhere. But maybe it would work for you, can't hurt to try.