How do I know when my rabbit will give birth?

I know my rabbit is pregnant. she's looking really big I'm just not sure how long she's been pregnant and when she'll have bunnies. I'm scared that she'll have them and there might be complications and I won't be there to see if everything's ok. I know rabbits like to be at peace when giving birth but so far she hasn't shown any aggression towards me. So do you think she'll be ok and what should I do?