C.V.
You are putting her to bed way too early!I have three kids who have all slept through the night by 8 weeks old.And have always been great at bedtime.Anyway in my personal opinion she wants to stay up later.She might be tierd at 6:15 but try giving her an evening nap and not putting her to bed until around 9-10 PM.You might try gradually pushing her naps back later so that her last nap is later and she can stay awake longer in the evening.I don't know what time her naps are but maybe she needs 4 naps.I thought my nephew was never going to sleep through the night.They were putting him to bed between 6-7.When he was old enough that he was down to one nap a day they would wake him up if they thought he was sleeping too long or too late.That only resulted in him being tierd earlier but not really being late enough for him to go to bed and he would not sleep through the night.