Well, I am 5"2 a very petite size 8 to 10 and Zach (my first son) was 9lb 3oz born. I did have an episiotomy and an epidural but I have to say it didn't hurt as much as I thought it would and he fared much better because he was a bigger baby.
My next baby is due in July this year and he or she is likely to be bigger. I am not worried though, trust the hospital judgment and if you are worried at any time tell your midwife. I am glad that I managed to have Zach naturally, the episiotomy wasn't as unpleasant as I thought either.
So don't worry hun, I'm sure that you'll be fine. I lived to tell the tale
Redhorse xxx