Amoré,
While laser is very quick and can often be much more cost effective, it only kills the hairs in the anagen stage. The complete cycle can be longer than a year. Any hairs that aren't currently active and won't become active before the surgery date will remain unaffected.
On the other hand, a proficient electrologist can also kill hairs that are currently visible even if they're not currently active (although it may hurt a bit more, as the needle may have to go past the resting follicle's depth.) Due to this, if the surgery is just three months from now and provided that you haven't shaved down there and know a good electrologist, I believe electrolysis might be a good choice.
Although some electrologists charge more for the area down there, it is much smaller and usually has much less hair density than the face so the final cost may not be too astronomical.