The numbers keep getting tighter (without a lot of evidence that leads to better outcomes). Last I heard, 6.5 twice is now diabetes, while 5.7-6.4 is “prediabetes” among those that believe prediabetes is a thing. A1C test - Mayo Clinic
Prediabetes is fairly controversial. Some doctors are very “ya either got diabetes or ya don’t, prediabetes is nonsense.” Others see numbers in the 5.7-6.4 range as not needing medication intervention, but a sign that lifestyle changes and diet education is probably a good idea.
Only one who can tell you personally what to do about it is your doctor. It’s going to depend on your other risk factors for developing full blown, actual diagnosis of diabetes how aggressively she wants to monitor or suggest diet and lifestyle change.
But, y’know, I’ve yet to meet anyone for whom achieving and maintaining a healthy body weight is a bad idea…