my daughter is 5 years old. her behaviour has changed a lot from last one year because of her cousin sister. my daughter used to be very polite, sweet , obeident and decent girl. Now she has become aggressive, loud and so much stubborn. She doesn't listen to anybody. Her cousin sister is like that only. What should I do? My sis in law would stay with us from now on. How can I make my daughter understand that she should not adopt her sister's behaviour? I am soo stressed. Kindly help. Thanks in advance.