For a teacher, the most important thing is not how profound your knowledge is, but that you have good moral character and professional ethics. Of course, if you are not good at math, develop other subjects and try to learn other knowledge well. In the process of being a teacher, you are also learning slowly, your knowledge will get better and better, and you can teach more good students.
Attention, math teacher:
As a teacher, you must love this industry. I know some normal students, and I was forced to go to normal school. I can imagine my later mood. So it's important to like this profession.
University professional knowledge should be solid, because it seems to me that too many middle school teachers never answer why. Personally, I think this is wrong, so it is better for universities to read more professional knowledge and have a certain understanding of mathematical culture and history.