How can a girl reconcile her commitment to the niqab with her desire to complete her university education, given strong opposition from her parents and siblings due to social and economic circumstances, and her feeling of guilt towards her parents?

You must thank Allah for your commitment to the hijab, learning the Quran, and honoring your parents. If you believe the niqab is obligatory, then you are not permitted to abandon it. If your parents order you to remove the niqab, you are not obliged to obey them, because obedience is not due in disobedience to Allah. We advise you to discuss this with your parents gently and wisely, explaining that circumstances have changed since the fall of the regime, and you can complete your studies and work while wearing the hijab. Seek assistance from righteous individuals who hold a respected position with your parents, and rely on Allah and trust in Him, for "whoever fears Allah, He will make for him a way out and provide for him from where he does not expect," and "whoever relies upon Allah, then He is sufficient for him."