I don't know how a person goes to work in the tax bureau.
In this case, first communicate with your boyfriend deeply, listen to his thoughts first, then tell him your thoughts, make a balance and then consider whether to go with him or stay in Xiamen together. People in love, it is best to be together, so that feelings will be stronger. No one can say what will happen in the future, just follow your heart. You can let him work for a while, see how it develops there, and then decide whether to go to Xiamen. This is my suggestion. I hope it helps you.