1. If you used a new lancet when you tested your blood sugar (using your mum's lancing device), there is no risk of infection.
2. Diabetes is not contagious, you cannot catch diabetes from someone.
3. Diabetes does have a strong genetic link (ie. it can be hereditary). The best way known to prevent diabetes is by keeping normal weight, exercising regularly, and eating a lower carb diet focusing on unprocessed natural foods; meats, veges, eggs, etc.