how early is too early?

Lately Cash has been waking up so early. Sometimes 5:30, 6:00, 6:30... any time before 7:00 is too early as far as I am concerned. I told him, if it was dark out, it was still night time. Sometimes he just wakes up and spends the morning - first 45 minutes or so of playing at his train table. It is stil dark outside but he turns on a light. The other morning I barely heard him say... hello guys, are you awake? Is it morning time? Hello guys, it's time to get up. It just struck me as a funny little conversation.