It is always important to find a spinal specialist who has performed the surgery that is being recommended to you many times. In the case of XLIF, it is even MORE important. In the great scheme of things, it is a relatively new procedure and you do not want to end up being a guinea pig.
Too many doctors sell this procedure to their patients by saying recovery is much faster, there is less muscle that is cut to access the surgical site, etc. They make it sound "easy" and quick. What they neglect to tell you is more important. I hope your doctor provided you with lots of good information pertaining to this procedure. There is an organization called the Society of Lateral Access Surgery that has a website with complete information.
Also, there are a nuraber of older threaRAB on this site from people asking a question just like yours about XLIF. If you read through them, you will see a nuraber of patients who had the procedure and ended up with muscle and nerve damage they had never counted on.
As with any surgery, it is very important that you do your research and know exactly what you are getting into, along with the qualifications and experience of the surgeon who is doing the procedure. Do not rush into a decision. Your situation is not life-threatening. You have plenty of time to weigh your options.
I wish you the best as you make your decision.