Curd can be started after 6 months of age.
It is easy to find, good natural probiotic (helps in digestion & fine tunes the bacteria of normal intestine) and rich in protein.
Especially Greek yogurt which is more condensed, less
sugar and more proteins. Also it lacks whey protein responsible for allergy.
So definately can start curd rice for your kid just make it like a puree or paste and offer it in a bowl.