My 3 1/2 DD still has a couple of hours sleep at about 12:30. (If I keep her up she is usually pretty nasty by tea time). DD2 usually wakes about 5:30-6am and all DD's are in bed by 7pm.
All kids do their own thing. DD1 used to be in bed early, sleep in and still have a lunchtime sleep!! Ah, those were the days.......I'd say enjoy your sleep in's: we no longer get them very often in our household!