J.P.
That's just the way some kids are- mine included. We have an early bedtime because they won't sleep past 5:30 and just end up crabby if they don't get enough sleep. Nothing we've tried has made a difference in their wake-up times! It's totally worth it to put them to bed early and get well-rested kids, even that early in the morning.... My oldest is over 3.5 and has been reading a digital clock for almost a year. He knows that whenever he wakes up, he must stay in bed quietly until 6. You'll probably just have to learn to live with the early waking!