Do I have any legal rights to see my biological sister?

My sister, from my dad, was adopted into a family not too long ago, shes 13 right now and im 19. Do i have any legal rights that allow me to see her? I also wrote a letter to her right before she was adopted but she never received it. Her soon to be adoptive mother, at that time, decided not to give it to her. Was she allowed to do that?