So, here are some things that are often not pointed out clinically.
The A1C measures the amount of glycation in your blood over 90 days, in theory. When your blood sugar rises, it attaches to the proteins in blood at a reliable rate/unit of glucose. Since blood cells, in theory, live for 90 days and then get replaced, measuring the amount of glycation in your blood should allow you to back into the average level of glucose in your blood stream over the last 90 days.
The issue is that in an average person, this is great. But if you are unhealthy (diabetic for instance) - your red blood cells won't live quite as long - in some people it is as little as 60 days. This means that instead of having the theoretical 90 days of exposure to glucose, they just had 60 days. Using this timeframe, the A1C would be 50% higher than what is actually read in a lab, and thus the lab is artificially reduced in an unhealthy individual.
In reverse, if you are very healthy, you may have blood cells that actually live longer than 90 days - and this would create an artificially high reading for someone like this.
So in other words, this is the problem with the A1C - if you are unhealthy your actual A1C could be as high as 8 if your cells lived longer, and if you're healthy and your red blood cells are living 120 days, your actual A1C could be as low as 4.3 - or anywhere in between. It's a good guess based on the average of the population, but it is not definitive.
In men, fasting glucose is a better indicator of health. If that is on the high side of normal AND you have an A1C of 5.7 - I certainly would not freak out about it, but it's a warning that you're going in the wrong direction.
An oral glucose tolerance test or a kraft test would be much better then either of these, but good luck getting a doctor to spend 3 hours with you when there is little clinical evidence of an issue.
As The Solution said, it can help to monitor your BG.
I wouldn't cut carbs actually either. You need to track your caloric intake. Fat is a more reliable inducer of diabetes than carbohydrate is - but ultimately caloric overload is the culprit. A lot of keto people think that keto is good for diabetics because it reduces blood sugar - and it may - because calories are reduced AND simple carbs are often eliminated and you thus reduce glucose on a glucose meter. But elevated lipids in the blood stream still need insulin to be used, and this is usually what led to the carb intolerance to begin with.
One final, a little crazy and off the wall thought - if you feel like you are carb intolerant, take a tablespoon of apple cider vinegar every day. It has a lot of quackery behind it on the internet, but I think it may actually improve carb tolerance to a small degree.