Questions about taking maternity leave

Ok so I’m 33 weeks and I’m having a csection at 37 weeks (due to previous csection complications)

I wanted to take atleast a week off before but last time the doctors would not sign papers until I gave birth!

Do you have the right to pick when you start your leave?

My company for disability asked when I was to start leave. If I gave them a date do they go with that and I just have to have the doctors fill everything else out or do the doctors get to choose the date 😩?