I've been "showing" for about the last 12 months! hehehe.

I think I can tell already, but I know it's just cause I know I'm pregnant and my diet has been terrible teh last few weeks, so I've gained a few kilos too!

BTW I don't think the weight of the baby has got anything to do with what sort of birthing you have. It's all about the head circumference and how broad the shoulders are!!!!! My son's head was too big and ended up being an emergency c-section. His head is still really big, he's not yet 5yo and has to have adult sized hats!!! He was 10 days over and weighed 8'9".
My daughter on the other hand had a smaller head (I had a VBAC with her), but she tore me really badly with her shoulders!!! Ouch! She was also 10 days over and 8'11".

Enjoy your pregnancy and your "Christmas" baby.