Being a student, you're in a prime position to judge whether returning to school after university appeals to you. But remember that there are lots of different aspects to teaching. You could teach adults, for example, or those with special needs. Then there's university: as a lecturer, at least half of your time is devoted to research, which brings you to the forefront of maths and science in general.
You can also get involved in the education sector at a different level and become one of those who decide what goes into the curriculum, or assess how well the education system functions.