My DD is the same age as your's. She will be 6 in April and just started Kinder this year. She goes to bed at 8pm and is usually asleep by 8.30pm. She sleeps until her older sister wakes her when she is getting ready for school at around 730am. During the school holidays she can sleep until 9am. If she goes to sleep at her own accord and wakes up without been woken she sleeps around 12hours.