My first goat is due in 5 weeks - no udder, no relaxed tailbone, no nothing yet... but she hasn't come into season since being mated in October, so I am assuming she is expecting.She is getting very keen on her food though...
Most of the growth of the kid(s) is in the last 8 weeks, and even then some of them won't look very pregnant at all.
It's a awaiting game... if she hasn't come into season she is almost certainly in kid...