I hope I'm not 'teaching my grandmother to suck eggs', but I hope the following will give you some peace of mind.
The usual signs of imminent kidding is when the goat gets restless, gettting up and down without settling, pawing the ground, turning her head and 'talking' to her sides. Obviously prior to that her udder will have filled up dramatically, her pelvic bones will become 'loose' so as to be able to permit expansion for the passage of the kid/s. It's not unusual for goats to delay kidding, they will kid when they think it's right - no matter when your calculated kidding date is! Of course regular observation is necessary, in case of too many days after the nominal kidding date and or prolonged efforts at giving birth which indicates difficulties giving birth - i.e. breech presentation, leg/s back, head back etc,. (I have had to deal with quite a few of these problems over the years from 15 Swiss breed showing and milking herd).
However, there mostly are no problems at all, just check the goat regularly and calmly without getting too stressed, the goat may pick up on your anxiety and become nervous herself.
One thing I always did after the kid/s had been born and dried off and the umbilical cord treated with antiseptic was to ensure that the kid/s suckled to get the important colostrum from their mother. After some hours I introduced them to the bottle (containing mothers milk), so they accepted the bottle readily and without problems, just in case there were any problems with their mother - it only happened to me once where the mother died and I was left with two orphaned kids - happily they not only survived on the bottle (using only natural goats milk from the herd - not commercial milk replacer) but they grew up well and won prizes!
I'm sure all will go well for you, just be patient and observant, look forward to hearing good news!