Badass & Guardian Rank / Challenges Question

(Sorry, if this should be in the Spoiler section, please move it, Mods!)

So, as I progress, I have been completing challenges (Kill 100 enemies with a pistol, etc) but, I cannot find a Badass Ranks screen, only a Guardian Ranks screen, and it says they do not become available until after you pass the game.

Are Guardian Ranks essentially Badass Ranks but they do not become available until after Playthrough 1 so you don’t become too OP from bonuses in your first playthrough?

Or is there a screen somewhere I am somehow missing listing all those challenges you have done / still need to complete?

Thanks in advance for any info!