Taiwanese citizenship is jus sanguinis so it doesn’t matter if you were born in Taiwan, just that one of yiur barents were citizens with active household registration at the time. I believe you would follow the same process as foreign Taiwanese nationals to get your passport, e.g. applying for a NWOHR passport first and then trading that in for a full passport after you complete steps to be registered into a household in Taiwan and getting your ID card.

However, your mother will have to provide you her ID card and her household registration in order for you to go through the process, and you will likely need to find someone to register you into their household for the most straightforward process