5 months. I tried at the “ideal” 4 months, but neither of mine were ready. Also, after you introduce the cereal, remember, don’t start with the sweet foods. Sweet Potatoes – things like that, usually the “orange” foods. Go through the green foods, first. Some babies struggle with the green veggies, when they’ve tasted the sweet veggies, mainly the orange veggies. Save fruits until the end. (bananas, applesauce, peaches, pears)
Cow milk, not before a year! Also, hold of on peanut butter before a year. If I remember correctly, they are starting to find some correlation to the early introduction of peanut butter. I can’t remember the recommended time on peanut butter, I waited for a long time, before I introduced peanut butter.