She's 5, has always been selfish and always struggled to share. With the school holidays its intensified. She's sounding petty and i'm struggling to enjoy the time I have with her. When DD's are taking turns she ALWAYS has to say, 'its my turn now' as soon as its DD2's turn, she ALWAYS checkes to see if she has more if things are being shared out, she's whinging about things when all her friends and DD2 are playing happily and she interrupts me constantly despite telling her not to interrupt when i'm talking. Nothing ever seems right unless its how she wants to be. She's has to be no 1 and has little regard for anyone else's feelings. I'm not used to this, DD2 (3) shares sweets, toys, most things, initiates taking turns etc. I've had enough now when she cried cos DD2 picked up a pen of hers. She overreacts in every situation where DD2 touches something of hers. I know children can be like this but how do I turn it around?