6AM wake up call!

For the past 2 days, Grace has been deciding to wake up at 6AM. She nurses and then I attempt to put her to sleep. She will fall asleep and after 10 minutes of being in the crib, she is awake. I let her coo and play until she gets fussy because I want to see if she will put herself back to sleep! I am guessing that she has playtime on her mind! She plays for about an hour and a half then goes back to sleep!