They were not born in the same month so they are not twins okay whoever wrote this they is easy I'm not stupid don't forget the month too
They are not twins because their mother gave birth to triplets.
You did not say that they had the same mother or that they were born the same year.
You've got to be kidding! Is that possible? So how did the mom get two same girls at the same time and date and even mom! They should be twins or else it doesn't make sense at all! Is that true? Could be triplets, two girls and a boy!
They could have been two of triplets (or quads, or quints ... or more).