maria, do you have a diaper on your dd at night? the most common reason my kids wake and have a harder time getting back to sleep is needing to pee.
and i'm not sure how early you are putting her to bed, and i doubt this relates to you,
but for my kids, a later bedtime does not mean sleeping in. i had to learn the hard way that they had to be put to bed at the right time for them....round 8-9. my eldest will pop up at 6 ready to go no matter what.