Ooooo Your mum is very lucky to have a Breeding Queen Ragdoll!

I have one but she is not registered. I would ideally like a GCCF registered one though.

Would you mind me asking where your mum bought her one from?

Spid gave you everything you need to know. Nearing the date I would set/or your mum could set her alarm for every 1.5 hours (during the night). If not she may miss the birth.

The next/box you make for her, I would also put this is your/mums bedroom so she can be there at all times. It is also useful for after the birth so you can check on kittens.

To totally prepare you could watch the birth of kittens of Youtube. Although you will still be nervous at the time, well, I was. Don't go for the clips with the 2 headed kittens though, that can make you a tad worried.