Many years ago when my now 22-year old daughter was a baby, she also had to have cereal early. She was only about 6 weeks old when I had to start giving it to her. I was nursing her, but she was not getting enough from me. I know that the "experts" don't want you to give babies anything extra until they are much older, but what they don't tell you is that babies go through growth spurts at various times during their infancy and need the extra nutrition. As long as she is not spitting it up after you give it to her, she should be fine with taking the extras. Don't worry so much at this point about whether or not she will be obese later on, just give her what she needs.