Buffer with TL084CN and resistors
Summary: For your case and your sensor is not important. your 100ohm resistance is negligible.

when your input resistance (\$100\:\Omega\$) * Input Offset Current_max (\$20\:\text{nA}\$) in the worst case generate \$2\:\mu\text{V}\$ offset voltage, your opamp typical input offset is in range \$3\:\text{mV}\$. so it is not important! 

Why we compensate the opamp:

opamp input is a symmetric architecture and if you change the symmetry this generates offset and gain temperature drift. the opamp input impedance is base on the substrate, for example for your case is \$10^{12}\:\Omega\$. when you put a resistance in the input, the quiescent current of the input pin generate offset voltage in input and difference of current in two sides generate different behavior in temperature. 

When R compensation is important:


when input_resistance* Input_Offset_Current_max > Voffset or comparable.
When the source has a high built-in impedance 
If you need a high gain system.
If drift in temperature is very important even \$1\:\mu\text{V}\$!