Each biological parent donates one of their two ABO alleles to their child. ... Identical twins will always have the same blood type because they were created from the same fertilized egg (fraternal twins can have different blood types — again, providing the parents do — because they are created by two fertilized eggs).

Would my sister have the same blood type as me?

No it doesn't. Neither of your parents has to have the same blood type as you. For example if one of your parents was AB+ and the other was O+, they could only have A and B kids. In other words, most likely none of their kids would share either parent's blood type.

Can a child have a different blood type than both parents?

Yes, a child is able to have a different blood type than both parents. Which parent decides the blood type of the child? The child's blood type is decided by both parents' blood type. Parents all pass along one of their 2 alleles to make up their child's blood type.