So, we're kinda back to square one: doe code. Generally speaking though, once the ligs start going, the kid(s) is/are coming very soon! IMHO, the best thing to do is to breath, relax, be prepared, and observant. Best wishes for a successful kidding this go 'round! 
If you've done much reading on here regarding kidding, you've probably seen the mentions of "doe code". It's true... every word of it. They will make you crazy waiting if you let them. Pictures really help as obviously, we can't see/hear/feel what you are. How did you arrive at the dates you mentioned above? Since you say she's lost her last 2 pregnancies (How? What happened? Full term losses? So sorry!) Do you recall when she bagged up during those? Since (if) she's been through this before, she should follow the same basic routine.
The best way to determine when she's going is a combination of a bunch of things. There's vaginal discharge; yellow/gold/creamy/rope like. The kids "dropping" into position. Bagging up, but this could happen weeks early or right at or just after kidding. Behavioral; nesting, stretching, pawing, "talking" to her kids, etc. And probably the go to for most is the ligaments on either side of her tail. They'll feel like "pencils" normally, but will stretch out and "disappear" in order for the kid to pass through.
Generally speaking, when the ligs go, she's very close, like within 24 hours. Now, here's the kicker: some goats have learned that we track this, so they've learned to slip their ligs, then tighten them back up repeatedly over time so it's not a "one and done" absolute either.
She is a lot lower in the last few days. Sides seem to have gone. No nesting but spending more time away from others and keeping out of any fights.
