Uh folks, let’s backtrack here. You guys went from 0 to Gforces in 3.6 seconds.
Ian wants to join his girlfriend, teach english and be legal all at the same time. While the citizenship stuff is nice and all, it is overkill to talk about it as he doesn’t need it to accomplish all three goals.
Ian, once you have your BA, you can get an English teaching job with a school. Once you’ve found a job, the school will sponsor a work permit and allow you to obtain a work-based ARC (alien resident certificate). This allows you to stay here and work as a teacher. You move here, be with your girlfriend and teach at the same time (and live happily hopefully).
If between now and graduating, you and your gf decide to get married, congratulations! Then you would obtain a resident visa based on marriage, what is called a JFRV (joining family resident visa). Then the ARC you get will be a marriage-based ARC. Once you have that, then you can obtain a job here without a work permit sponsored by your school/employer.
Then after many many years of marital bliss, you can consider becoming a Taiwan citizen. As Poagao says, the process does at the moment require a renunciation of previous citizenship process. Which would then make you eligible for the fun opportunity of serving for the ROC military. If you’re unlucky, you might draw lots and end up in Matsu or Jingmen… but we’re a bit ahead of ourselves.
Anyways, if you need further assistance, contact ML McLean and someone will help you.