My baby is 4 weeks old today and at her last doctors appt her doctor told me she has acid reflux, which is why she spits up A LOT. He told me put a little bit of oatmeal in her milk to thicken it up so it’ll stay down. But, I feel like she still too small to start feeding her oatmeal (cereal) . I thought I shouldn’t start feeding oatmeal until around 3 months. Thoughts???