My NZW rabbits take about 30-32 days from mating to birth.
bunnies usually get be pregnant early 4 months... if you keep males and female bunnies together the males will have sex.
bunnies can become pregnant after 24 hrs of giving birth. around 21 days to have the kits(babies). I hope your bunny is okay.
you can check with your vet to check her out.