In the end, I decided to make my first submission to someone whom I don't personally know, but whom I had a passing acquaintance with through the vagaries of the Internets and LiveJournal. From reading his blog I knew that whatever his reaction to the story was, he'd respond to me both honestly and respectfully.
This is not always the case with editors, and I knew from experience that an unreasonably harsh response at that point in my development as a writer would thoroughly derail my writing. It happened before, back in '91 or so. I didn't want to lose another decade.
So I sent the story, and he rejected it a few days later.
I was disappointed, and I didn't quite understand what he told me the problems with it were. Or how to overcome them. But he was right to reject it. Looking back at that story six months later I saw all manner of mistakes. Bad grammar. Poor pacing. Inadequately fleshed out characters. Linguistic constructions that I had thought clever at the time. (ohgodthecleverlinguisticconstructions!)
I am glad I wrote the story, and I'm glad I submitted it. I'm also glad that it was rejected, and am thankful for the manner in which it was done. It encouraged me to keep writing, and it showed me where I could improve. That rejection letter was one of the key points in my development as a writer. Thanks, Jim.
What of the rest of you, fellow scribes? How went your first submission?