Potty training

How do you know if a toddler isn’t ready to potty train? She will tell us that she has to go pee or poop and sometimes it’s before she has to go and sometimes it’s already happened when she tells us. She does go pee every time she sits on the toilet and goes poop when she needs to. I expect accidents to happen when starting to potty train I’m just not sure if maybe she isn’t ready or if this is something that is normal? Any advice would be greatly appreciated! This is my first time having to potty train.