My suggestion would be push for a referral for a paediatrician.
In the mean time I would put her on a toddler formula rather than plain cows milk.

My eldest has an aversion to many textures & for many years would eat very little. When the paediatrician saw him & hear what he ate she ordered blood tests to check for deficiency, but because he was on toddler formula (with added probiotics) his blood tests came back fine.

Is it possible your girl has texture aversion? Or like others said what are her tonsils & adenoids like?