Let baby set schedul
Any 6 wk old that has been feeding
& growing well can be left alone to sleep
as long as 8 or more hours.
Their intestines has food they are continuing to digest & use during this period & if baby can deal with it & thrive there is no reason to wake her.Babies don't sleep more than 4 hr without cycling to a lighter sleep state so the fact that yours can settle back & sleep longer is wonderful.