food question

I know this is a somewhat divided issue but I want some feedback! LO is 16 weeks old and I am having some difficulty keeping up with her demand for breast milk. She has been EBF up until this point and I pump at work so she can take a bottle with my parents (my daycare!). Is it too soon to introduce food? I was thinking peas or prunes or something. She seems hungry and WILL NOT take formula (we tried a couple times). She has very good head control and no other medical issues.