I was diagnosed with an HbA1c of 88 in April.
A month later I was regularly gettings readings in the 5's. My Fasting levels remained higher than that until about September, and are now usually in the high 4's low 5's.
I started on 3x500g Metformin immediately after diagnosis and ditched virtually all Carbs as well from that day.
My HbA1c 3 months after diagnosis was 32