I've been giving my baby oatmeal cereal for about 3 weeks now. Can I give him organic jar food that's for 4+ months babies? He's 5 months now.

What's the hurry. 50 years ago infants were fed solids early & frequently to make up for deficiencies in the evaporated milk formulas moms made at home.Today early feeds are an antiquated practice & do not add to the child's nutrition.Today solids are viewed as a tutorial to transition baby to the table. Starting at 6m as the tongue thrust fades & baby begins to sit is early enough.
Yes. start with single fruits or vegetables not dinners or combinations use new product every week only. checking to make sure that the prior food was well tolerated.