my doctor said the same thing. I did it twice, then after reading about rice cereal and its lack of nutrients, decided I will just wait til 6 months and then I can skip the whole stupid rice cereal thing altogether. My friends and ppl online have told me rice cereal is constipating and upsets their stomach, a main reason why I choose not to do it. Plus it's all starchy which isnt good. I heard that a great first food can be avocados smashed and pureed, but at 6 months. so I'm waiting til 6 months then I can start giving her veggies. Your doctor is getting her info from outdated times. It's just standard information, it's not the words of the gods or anything. Even though my baby's pedi said it's fine to give my baby rice cereal now, shes 4 1/2 months, I choose to listen to myself instead. In general, the longer you delay solids, the better. so it's better to start at 6 months than at 4 months. When I was a baby I didnt even have solids til 8 months, and I did fine. however, that being said, some babies are ready a little earlier. some signs that they're ready are they can sit unassisted well for at least a little while, and they grab for your food literally and try to put it in their mouth. My baby did this the other day, she grabbed a handful of my rice i was eating while holding her, but luckily I took it out of her hands since it was filled with salt. But bc she cant sit very well at all yet unassisted, I am waiting.