Do you feel like you know the difference between a mint error and a "damaged" coin? Do you know the difference between an error and a variety? If not, you should take the ANA's correspondence courses ""The Modern Minting Process", and "U.S. Minting Errors & Varieties." They are excellent courses which will teach you all the fundamentals (and more) about errors and varieties. You will then have a solid foundation to grow and learn as an error or variety collector.
Here is a link to the ANA's correspondence courses: https://www.money.org/diploma-program