this_person
Just get your story out there and then deal with the editing afterwords. Creative writing isn't about having great punctuation or the correct tense, it's about emotion, feeling, soul, and how you perceive things to be. Deal with the technical parts later, that's what I say.
Well, the creative part of writing is about emotion, feeling and soul - but you really DO have to edit your stuff. Honestly. That's the WRITING part.
All the writers I've known (mostly guys with only a few stories out there, like Doug Lain and the idiots who handed me their stories for the Greenhorn Tribune and the other rags I worked for) had to edit and re-edit their stuff. Expect it.
Just don't stop - or you're not writing. You're preening.
See: if, for instance, your emotions, feelings and soul do not immediately appeal to the reader, they'll look for any excuse to stop reading. Bad grammar is #1 on that list.