I have a different approach. Considering you are using an ADC with VCC as reference, implementing the sensor circuit as a simple voltage divider forms a ratiometric circuit, that has resistor accuracy (and ADC imperfection) as only error terms. As a disadadvantage, you get an additional non-linear term y= a/(a+x) respectively y=x/(a+x), depending on the sensor position in the circuit, in the signal chain. It has to be reversed to calculate the temperature. But a NTC is highly non-linear any way, needing a table or ln() calculation to get the temperature, so the additional term shouldn't be a problem. An ADC reading to temperature table could include the voltage divider.
If the ADC resolution is sufficient, I would also drop the OP circuit.