My hba1c is 5.9%.is it good enough?

Pre-Diabetes: No. It represents elevated blood sugar levels that are unhealthy for at least the last ninety days.

Borderline, so no: You have a borderline result. You're in the pre-diabetic range. Normal is up to 5.7. Pre-diabetic is 5.7 - 6.4. And diabetes is anything 6.5 or above. Go get a glucose meter and check some fingersticks. Completely NL in the AM fasting is 70-100. 101-125 is borderline, >125 is diabetes. Check out this link from the NIH: http://diabetes.niddk.nih.gov/dm/pubs/A1CTest/A1C_Test_DM_508.pdf