Aw puppies, I'm so sorry!
TBH, I was reeeeeally freaked out about tearing/being cut when I was pg. I couldn't get the worry out of my head.
However it was the very last thing on my mind when I actually went into labour. In the end I had a minor tear, and I didn't feel it happen - I was so surprised when they told me I'd need a couple of stitches. And they didn't cause me any problems either.
I know it's a dumb thing to say, but please try not to stress about it. Like others have suggested, fill your head with positive information and stories - read lots of great and helpful books (e.g. the Thinking woman's guide to better birth, new active birth, Spiritual Midwifery) and ignore people who want to scare you. That is more about them than about you, KWIM?
Read Hoobley's post again (OMG - I have to share the love, but that brought tears to my eyes, Bx!) and probably some of those words will come back to you as you feel those first pains. You are going to be great!