My 11 week old wakes up somewhere between 35-45 mins for about half of her naps. Her first nap of the day is usually great (and I have to wake her up from it), but the other naps vary. What causes the 45 min wake up? Being over tired or under tired? Right now her A time ranges from 1 hour to 1 hour 20 mins, I'm not sure which would be better for her at this age? I usually try for an hour because she starts fussing, but perhaps A time should be extended at 11 weeks?