If there are snores or long interruptions, her adenoids / tonsils may be interfering with her sleep and causing apnea episodes—which likely wake her up.

Our six year old demonstrated this when she was 3/4. She would wake up and come into our room nearly every night at around 2:00 or 3:00. For a few nights I would go in to her room around midnight and listen / record her breathing. We got her in to an ENT, played a recording of her apnea for him, and he scheduled her for a tonsillectomy the same day.

It’s been /much/ better ever since. She still tends to wake up earliest and sometimes wakes in the middle of the night, but it’s rare. Most importantly, she’s happier and healthier.