Im 40 years old my fasting plasma glucose is 6.0 it is normal or high?

Not normal: Fasting glucose of 6 mmol/l is equal to 108 mg/dl which put you in the pre-diabetes range (100-125 mg/dl). If this is the first time you see this, repeat it again to see if this was not just a lab error. If you truly worries about diabetes, ask for a a1c test on the next blood draw as well. This test is more stable and give an average of your last 3 month blood sugar.