I was never actually diagnosed as pre-diabetic,but was told at the end of 2013 at age 71 that I was a T2. I was having regular (approx) 6 monthly medical checkup/reviews, and it was apparently picked up in March that year, but I wasn't told until, and had the diagnosis confirmed after, my November review. However, after immediately cutting out all sugary, then al high carb foods, i've had pre-diabetic level HbA1c results since Feb 2014 (see signature) - though I'm identified as well controlled.
Robbity