When I switched from breast milk to formula I didn't know I was only suppose to give Elisabeth a bottle every 4 hours…

When I switched from breast milk to formula I didn't know I was only suppose to give Elisabeth a bottle every 4 hours instead of 2 she's only three months and drinks 7 ounces already and still acts like she's starving I even tried putting a little rice cereal in her milk she's still hungry 😣 if someone is eating she stares them down and reaches out can i start her on rice cereal or wait until she is 4 months🤔