Astrology does not differentiate people using a caste system. There are no axioms in astrology that one will be born as a Brahmin or a Kshatriya or a Sudra or Vaisya. Caste system is society made and basically every one us are alike in all respects. Your parents might not be so enlightened about spirituality and they just follow the rules of society prevalent in the place they are living. And as a daughter, you are obliged to listen to them if you so wish.