L.M.
How think was it when you mixed it? It shouldn't be think like adult oatmeal...there should not be any chunks. I would try it again but start with Rice cereal...she is definately not too young (barring any developmental concerns that we are not privy to).
Most babies start with some in their bottles but my son never liked it in the bottle so we always spoon fed his (and he liked it thicker too). My daughter liked it a bit thinner.