First, was your labs done fasted? If not, then the 101 BG would be based on when your last meal was and may not be an issue. If it was fasted then that is on the higher side.
However, your AIC is not that bad. I would get a glucose meter and check your fasted BG in the morning for 3-4 days straight so you get a better picture of where you stand before you start adding in supps like metformin or berberine (not that I am against them at all but I don't think they should be default).
If your fasted BG is consistently above 90 then I would first recommend adding in ~30 min of cardio 3-4 days a week. That alone will greatly increase insulin sensitivity if your are currently not doing any cardio. Again, I would do this before adding in metformin or berberine.
The other obvious thing to do is look at your diet and if your body fat is above say 14-15% then I would look at trying to bring that down a bit.
If after doing that and your fasted BG is still high then you can look at adding in metformin or berberine. But if it's still high then I would also suspect it would be due to GH and then I would recommend taking a break from the GH until your fasted BG is under 80-85.
If you really want to know your insulin sensitivity, then next time you get your blood test done have them measure your insulin. Then you can use your insulin level & your fasted BG to calculate your HOMA-IR (they have a calculator online) to determine insulin sensitivity.