Mine was 3cm and the only major symptom at the time (that I realized was related) was sudden hearing loss. Since then, I've been able to point to probable symptoms that I had leading up to that point.. Like, I had 3 or 4 sinus infections that year... gradual hearing loss but not noticeable to me (but was to others).. And, one fainting/seizure that I suspect was AN related. Also, looking back, I had frequent headaches...
Like you, the only option I was given was surgery...
I'm confident the surgery will go well and recovery will be slow but steady.. Be confident in your surgeons. There are many testamonials on this forum to the fact that there IS life after AN. In fact, next weekend I'm going camping again for about the 10th time or so (lost count) since my surgery with my son.. and the following weekend with my daughter. I've been swimming, biking, jogging, hiking, etc... There IS life after surgery. Believe it.
Regards,
Brian