It means your blood sugar over a period of the last 2 months or so has been extremely high. Anything over 6.5 is confirmed diabetes. 13.0 is putting you at risk for complications. I'm assuming your doctor is scheduling you for a follow-up visit to determine a plan of action to lower that A1C, consisting of diet, exercise and some form of medication.
Yes, she is right. Your sugar was way too high. You would want your number to be 6 or below.
I forgot to add that if you are overweight, losing weight will significantly help in controlling your blood sugar. In addition to the visit with the doctor I would encourage you to learn as much as you can online about managing type 2 diabetes. This condition is one which if well managed complications can be avoided; if not, there will be problems. There is a lot to learn at first, so take it one step at a time. I recommend getting a meter and beginning to test your fasting blood sugar (you want it, ideally under 100) and your blood sugar two hours after eating and those numbers should be under 140. Do not be discouraged if right now they are way higher than that as your A1C indicates. You might have had diabetes for awhile. With the right combination of lowered carbs, weight loss, exercise and medication they will start to come down.