P.M.
She's young... wakes up alone in a very dim to dark room, might have had an odd or scary dream and just wants to feel safe with her Mommy.
I've bed-shared with my now 5 y/o daughter since birth and she's decided she's ready for her own room and bed. She also goes on to say "Mommy if I get scared, can I come back and lay with you?" - I tell her ABSOLUTELY. We have yet to organize and put her bed and room together yet - but it should be done soon.
Her choosing to leave the family bed is a very big girl decision and we've been very happy and supportive of her about moving up into a Big Girl room. By her making up her own mind, it's been made into a really big deal.