Just know that there's no nutritional value for them at that age and that the earlier you start, the higher the chance they will develop allergies. It's recommended to wait til 6 months
My pediatrician said 6mo but I'm really not going by that, I'm starting at 4mo then at 5mo I'm gonna start baby food. I really don't understand why they keep changing the age limit on foods, my mom started feeding me and my sisters rice cereal at 2mo and baby food at 3mo and we we're fine, weren't over weight and had no issues with our digestive system. But i really thinknit all depends on how comfortable you are with and when you decide introducing cereal and food.