Let's face it. Getting criticism sucks. It's great in the long run, but the moment when you read a note pointing out a major plot flaw in your manuscript, or a note condemning one of your characters, can be one of the most difficult moments to bear in your writing career. I've done a fair amount of revisions with both my agent and my editor, so I'm here to tell you now:
It doesn't get better.
You won't just be killing babies; you'll be killing children, teenagers, even, fully formed scenes and subplots and perhaps even characters.
Editing is a ruthless process. With LIKE CLOCKWORK, I cut several major subplots, drastically reduced the role of one character and increased that of another, and added a subplot that entirely changed the story. And I'm only on the first round of revisions. Nothing in a manuscript is fixed; as authors, we cannot get attached to our initial vision of a story, because it will invariably change with time, distance, and feedback. It's something I struggle with constantly, although I'm always happy with the result of my revisions.
So ask yourself: can you handle this? Can you handle killing your babies and children and teenagers? If you're serious about publication, the answer should be yes.
Revision sucks. We push through. And in the end, our books come out that much awesomer (which is not a word, but I'm using it anyway).