...I am bit surprised though that they haven't started you in meds straight away if your fasting BG is 12. From that level it is pretty unlikely you would be able to get satisfactory control (ie Fasting BG around 7 or less) with diet alone.
I started from a similar position over 3 years ago and went straight on to metformin and now have to take sitagliptin as well to keep it at a barely satisfactory level.