Question on bass grading/theory

[school daze]

Hey, new to the forum! Iv been playing bass for a number of years in bands and other things, self taught.
Iv reached a point where I need to learn some solid bass theory to move forward as i know none atall.
So i was thinking of just going through the grades starting from 1. Just wondering what your guys opinion is on
getting some theory down. Also how would i go about doing these grades?

cheers guys

Joe