DD used to go to bed at night between 7:30 to 8 pm and will wake up between 6:30 and 7 am in the morning. She's still taking 1.5-2 hour nap in the afternoon, usually between 1 to 2 pm. For the past two months though I notice her bed time is getting later and later.....I'd do her routine at around 8 pm and she wouldn't go to sleep until 9:30 pm or a bit later. She'll stay in her room, but will talk and sing to sleep and still wake up between 6:30 and 7:00 am in the morning and then she'll get tired by the time she came back from half-day preschool, which is around noon. I tried to send her to nap after lunch around 12:30, but she usually ends up nap at around 1 and sometimes 2 and wake up at 4 pm sometimes. I started to wonder if 4 pm is too late to wake up from a nap for her and it pushes her bedtime to 9:30 plus. Should I limit her nap to one hour ? I prefer that she doesn't go to bed that late.

What's an appropriate bed time for this age ?