C.M.
Well...I hate to say this but I think that is normal. It seems like every few months one of my kids changes their morning schedule. Last week my 17 month old was waking up at 5:30. He has at least pushed it forward to 6 something the last few mornings. You could try putting things in her crib to see if that keeps her busy. Maybe like a sippy cup of water. A book. A few toys. OR just let her fuss. OR just deal with it, have your coffee ready to be made (I have mine programmed but have had to start it manually because of his time change) put out a bowl of dry cereal for her to snack on, drink your coffee and watch a little TV. As you can see--I have chosen the just deal with it method. I do gripe about getting up so early, but I love the peacefulness early in the morning. Just sitting there and watching a little TV while drinking my coffee gives me some time to wake up, relax and just think before my other child wakes up.
Good luck!