On the whole I agree with the others, those hba1cs are effectively the same. So well done for not progressing any further. But given that you're slim and haven't had a significant reduction of hba1c via diet I've got to ask, have you had any tests to confirm you're prediabetic T2 rather than prediabetic T1/LADA? LADA can progress very slowly and be stalled for quite a while by means of drastic carb reduction. Your GP will probably assume you are borderline T2 just because of your age, but you can't know that without doing a test. I'd recommend a c-peptide, which measures the amount of insulin you produce. T2s produce lots because they are insulin resistant, T1/LADA produce little because their insulin producing cells get progressively destroyed. Though T1 is much rarer than T2 (1 to 10 ratio), nearly half of adult diagnosed T1s get initially misdiagnosed as T2.
And another possibility is that you haven't cut out as many carbs as your body needs you to. If you want to list a typical day;s diet here then there will be plenty of folk to make suggestions.
