"Shitty First Drafts"

I keep hearing people say that writers need to think of their initial work as "shitty first drafts" (from a book Bird by Bird written by Anne Lamott).  I'm trying to take this into consideration as I write.  Instead of being a perfectionist all the time (that's me!), sometimes I just need to shut off my inner critic and just write.  Tonight, I made some progress on my novel because I treated it as a free write (though I even edit those as I go along).  It's definitely awful, but at least I'm getting somewhere, right?  Tonight I drafted chapter 5 and the beginning of chapter 6.  I'm going to rework them a bit before submitting them, but at least I got that far!  I've been turning out about a chapter every two weeks (which really comes from my school schedule of submissions more than anything else), so this is huge. 

My instructor and I spoke over the phone yesterday and she mentioned that maybe I should considered taking part in the NaNoWriMo in November to get the novel drafted (though unfinished - almost nobody can turn out a good, page-turning book in a month).  While I'm not sure if this is the right path for me, I'm realizing I need to stop worrying about everything being perfect.  Even the content or writing that I think is fabulous may eventually be cut or completely edited in the end.  When I pick up this draft in a a few months (to get some distance from my work) I'm going to see all sorts of issues I can't see right now.  Who knows if my 'good' writing will really turn out to be awful...