Susie, I agree with what everyone else before me has said. This is a major decision with lifelong consequences, so you want to be really certain you're making the best choice for you, before you seek any type of treatment.
In answer to your questions, radiation -- whether GK or CK -- almost always offers far lower risk of facial paralysis compared to surgical resection. For a small tumor such as yours, however, and with the good hearing you still have, it's probably not so clear-cut whether radiation or surgery offers you the best chance of hearing preservation. In cases where the tumor is medium to large size and the hearing nerve is already very weak (not your situation), radiation generally offers a better chance of hearing preservation compared to microsurgery. (The result of an ABR test -- which indicates the electrical continuity of the hearing nerve -- is regarded as a good indicator as to whether or not a significantly damaged hearing nerve can withstand the further trauma of surgical resection or not; you might ask your surgeon for an ABR test if you haven't had one performed yet, to confirm your hearing nerve is still in robust condition.) Between GK and CK, CK offers slightly higher odds of hearing preservation (generally 75% for CK vs 65% for GK, but this is averaged across all tumor sizes and locations; for small tumors, the odds can be significantly better.)
There are other factors to consider. Perhaps most significantly, radiation poses no risk of CSF (cerebral spinal fluid) leakage and generally has a much shorter recovery period. There is generally much lower risk of chronic headaches following radiation, although middle-fossa approach poses a lower risk than retrosigmoid. Headaches after surgery are generally thought to be caused by fine bone dust getting inside the cranium when the skull is cut open to gain access to the tumor. Retrosigmoid approach carries about a 15% risk of chronic headaches post-surgery. If I remember correctly, middle-fossa -- which your surgeon is planning for you -- poses much lower risk of chronic headaches. If your surgeon has not gone over all these risks with you, I recommend you ask him/her to quantify each risk in percentage terms so you know whether you're exposing yourself to higher risk than you assumed and are willing to take on. Have them put a number on it (e.g., 15%) so you know exactly what you're getting yourself into. There's no "do over."
I always groan when I hear a surgeon say surgery would be more difficult after radiation, should the tumor grow again. The best surgeons emphatically state that this is not the case in expert hands. Personally, I would worry about any doctor that makes that statement (especially because the chance of regrowth is statistically low -- and about equal -- for both surgery and radiation).
But the main deciding factor, as others have noted, is what your gut is telling you. Especially because your tumor is so small, there is no reason to rush into having a treatment you're not completely certain is the best option for you. If it were me, I would postpone the procedure until I had more clarity and resolve. And if you haven't received a second (and possibly third) opinion, this is also something you should strongly consider before moving forward.