I want to become a teacher through tafe then uni.

18m thinking of dropping out of secondary school and going to tafe then uni to teach secondary school like general maths. Too late to fix my atar so can’t go to uni straight away, but i still want to teach others maths, what are the steps all i know is getting a diploma then go uni then find a job ig, i can learn methods in uni.
Any tips or what stuff i should avoid????