My mom is a fraternal twins
Is your mom an identical twin or fraternal? My doctor said the chances are high if your mom or grandmother have a fraternal twin. Identical doesn't affect passing twins down and your baby's father's side doesn't count either. I was scared to death of having twins my first time to and my grandmother is a fraternal twin! But they checked everywhere and I'm only carrying one.
Twin gestations can be easily seen by ultrasound. Get it done at about 8-9 weeks. At that time, if twins, chorionicty and amnionicity can be accurately determined. That is vital to know for the proper management of the pregnancy.