Ds had that issue and we waited until he was one. He was on breastmilk only and no dairy but once he was on solids we slowly introduced dairy. Very little to begin with because, as yoiuve experienced, a little can ruin things for a few days. He was probably closer to 10 months. I was terrified to try but it seemed that slowly worked best and now its a total non issue. Its amazing BC If I had a piece of cheese and he nursedlayer, we immediately noticed it in his comfort, behavior and sleep.