Yes, I think she is about ready. It's usually sooner (within 2 to 12 hours) but if things don't progress into hard labor and pups within 24 hours of the temperature drop you should call your vet. She may begin wanting to go out a lot, if you do tend to let her out alone, do not let her go outside alone now or anything, you have to watch her like a hawk. There is a lot of breeding and whelping basics links and information in the link below for you (protocol, normal, not normal, danger signs, common problems ect.). Good Luck.
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q3525724.html#a2810229