Even if you are overweight - it is not conclusive that you will develop pre-diabetes or diabetes.  So to help you add to the "risk list" and hopefully propel you to the nearest doctor for a fasting blood sugar and general evaluation, here's the list:

1- Physical inactivity

2- First degree relative with diabetes

3- Member of certain ethnic groups  that are "high risk if overweight" - African American, Latino, Native American, Asian American, Pacific-Islander

4- Women who delivered a baby that weighed more than 9 pounds or that had gestational diabetes

5- HDL level below 35 and/or triglyceride level above 250 mg/dl

women diagnosed with polycystic ovarian syndrome

6- Impaired glucose tolerance test or fasting blood sugar previously

7- Presence of heart disease

If you don't have these risk factors then at least by age 45 you should be tested as a baseline determination and if the reading is "normal," check ups should be every 3 years - sooner, if you gain significant weight.