Giving my 3 month year old baby oatmeal?

I tried doing the same with my son as far upping the ounces but my pedi suggested that 6 oz was too much at that age.my sons 19 lbs at 7 months.doctor says he's right on track.some babies r lighter and some r heavier but oatmeal that early isn't suggested.a single graib rice cereal would be better but I doubt he'd be capable of eating off a spoon that early or understand his tongue reflex of how to use it to push the food to the back of hIs mouth then swallow. Maybe he's not hungry...maybe he's understimulated or has acid reflux issues which your thinking is a cry for food...possibilty.anyways hope I could help.my son had reflux and once they figured it out his fussing got alot less and the medicine seemed to make his eating habits slot more normal for his age.