How long should I stay in my first job?
There is no easy answer to this question that arises anew every year. The trite answer is: until you feel ready for a move. This may be after a couple of years or it may be longer. My own career has been a mixture of three lengthy spells in particular posts and a number of short periods in other jobs. In one case, I knew the post was wrong after three weeks, but I stayed for a year to gain experience.
With a working life that is likely to extend beyond 40 years, it is worth giving your career some thought. There are many opportunities for teachers and it is worth trying to keep yourself in the driving seat.