How much do genetics matter for type 2 diabetes? my grandfather was diagnosed with diabetes at 63, and i'm worried i may get it in the future also.

Nature vs nurture: Genetics matter. But everyone has genes that increase risk of something. If your biggest risk is t2dm in your 60's, consider yourself much better off than a lot of people. The genetics of diabetes is complex. Not one gene but many genes. You may/may not be at risk. Either way, a healthy lifestyle (exercise, normal body weight, healthy diet) will go a long way to prevent diabetes later on.