I was dx'd in July with a "mere" 6.8. I just tested A1c at 5.5.
Remarkably, I was in the depths of depression, and for months previous, my diet was ice cream, cookies, and deli sandwiches, so the reality is, I am lucky it was "only" 6.8 I did fail the tolerance test quite miserably tho
The look in my doctor's eye was a pretty good motivator, as it was obvious he didn't think I would bother to do anything about it. I visited him just last week, and let him know how wrong he was. Felt good.
The biggest motivator was a desire to find out how low I could get it. I am 54, out of work, divorced, last child just moved out, and so I had time to focus on it. Hardly the same dramatic drop as yours, but it made me feel pretty good to know that my body is not completely broken, just yet. I suspect it will rise a bit next time, due to life circumstances, and the simple fact that I am having trouble with so many facets of life, that I am not sure I can maintain the focus.
As a side effect, the 21 pounds I lost has me punching new holes in my belt, and I can hike in the mountains a lot longer than before Plus my blood pressure took a major dive below any numbers I had ever hoped to see.
Congrats to you, keep at it. There is much to be grateful for, and much life left for you to enjoy. Get the most that you can from it.