my son is 5 months we got the go ahead at 4 months cause he had awesome head/neck control were just now starting to do them everyday

5 months, I wanted to wait til 6 like suggested but wasn't realistic for our daughter lol but even then for a month we only fed oatmeal once a day for a month and when she turned 6 months we have been starting twice a day (oatmeal in the am and baby food in the pm)

7 months

My son was given the go ahead from his doctor at 4 months for cereals (he had reflux so she had been wanting me to give him it) but he didn't have anything until closer to 6 months.

6 months. You really shouldn't any sooner.