When am I ready for the next level?

Hi everyone... I just randomly heard an intermediate level podcast and realized that I barely understood any of it. Right now I am at mid-newbie level I would say. I was wondering that by the time I am done studying the newbie and elementary podcasts (thoroughly of course), will I be able to understand everything that Jenny says in chinese in the podcast? Also, in general, how do you know when you're ready for the next level? I know I can just check out a podcast of the level above to see if I'm ready for it, but what if I'm not? Do I just study random vocabulary till I am?

Wow those were more questions than I thought I would ask :)

Thanks guys!!!