Neophyte? The apostles didn't teach the assumption of Mary or that she was sinless. Yet the Catholic Church demands that their followers believe that. Paul said anyone who teaches something they didn't was to be considered accursed as it was "another gospel".
As you reject the teachings of the Catholic Church, Sacred traditions and the Magisterium that The Holy Spirit inspires and protects the Church from error, you should be aware of the 6 sins against the Holy Spirit:
Presumption
Despair
Resisting the known truth
Envy of another’s spiritual good
Obstinacy in sin
Final impenitence