The day you have your baby is considered day 0 so Saturday would be day 3.
i was told by midwife in my last c section that if bubs is born in morning of that day its day 0 if bubs is born in afternoon its day 1.

I stayed 6 days for all 3 c sections altho i had other problems that needed monitoring.
You can go home when they are confident you can be mobile. the next day they get you up and walking and they like you to have done a poo before leaving hospital 3 days should be fine. PLus they have early discharge programs!!