I started feeding my daughter rice cereal at the age of 4 months. She was consuming 7 oz of milk about every 3 hours, 5 times a day - total of 35 oz daily. Pediatrian said go ahead and feed her rice cereal. Start off with it very liquified and runny and increase consisentcy as she gets use to it. Use the formula/breast milk in the cereal so she still get the nutrients.
Started off feeding her 2 tablespoons in morning and two at dinner feeding. She did not bat an eye. With her first bite it was as if she had been waiting for this moments for months. I think she enjoyed the feeling of food in her belly. Milk consumption dropped to 6-8 oz every 4 hours 4 times a day. Ped said as long as she gets a total of 25 oz of milk a day she is good. She gets 6 oz bottle when she ate the cereal and 8 oz bottle during the two day feedings.
My daughter was 8lbs 7oz when she born and grew consistently. I think bigger babies are ready for solids sooner.