Understanding on frequency compensation on driving capacitive loads with an op-amp
In addition to the nice answers you will no doubt get about this theoretical exercise, I want to add a practical word of cautions:
Capacitor values have large tolerances and Class II ceramics have strong DC dependence. Also the output impedance is not well known typically.
So even though you did all the calculations correctly, you might still end up with oscillations. To find a good value for the feedback capacitance will require some experimentation, if you really need the maximum possible bandwidth.
If you anyway are only going to use a bandwidth much below the possible bandwidth, you can and should be very generous about the value of the feedback capacitor. Making it larger than its critical value has no bad consequences other than restricting your bandwidth. Restricting bandwidth is often a good practise to help against interference and aliasing. By way overspeccing this capacitor you also make yourself independent of component variations and guarantee that your designs always work.