Nursery for baby Chin?

Thanks to the great advice here from lovely, friendly, patient posters :thankyou:
I'm going to be a Mum to one Chinchilla :bliss:
I have the cage well on the way to being set up for my new arrival but......
Having read that babies don't know when to stop I'm concerned about my set up :confused3:
As my little one will have just left home should I limit the amount of space available until he/she has grown a bit? :hmm:
As in split off 1/2 the cage and make a nursery or will it be okay to just have everything available?

Is there an age when they can start dust baths? Do tinies need less depth of Chin sand?

Thanks for all your patience