When my daughter was about that age, we bought her a special clock that can be set to turn green at a specified time each morning. We told her she wasn't allowed to get up for the day until it was green. I was amazed at how well this worked for us. Now that she is older she still uses it, but as regular alarm clock.

https://www.amazon.com/Teach-Talkin...6568943&sr=8-4&keywords=kids+alarm+clock