C.:
I have a nearly 4 year old who still prefers to sleep with mommy. I work in education, so there are times when I am home for several weeks at a time, and then I work full timet the rest of the year. I have notices two things,
one: when I am working, or the week is really busy, he tends to want to sleep with me more.
Two: when a big change is taking place, or something new is happening (even good things) and he feels a little insecure he tends to want to sleep with me more.
He has identified this himself and tells me he needs more "Mommy Time".
I also expect (and have conferred with others) that being a single parent affects it. The kids only have one parent's attention on a daily basis instead of two.
Children need the security of closeness and affection. When they feel they don't get enough, they try to find ways to get it. Getting up in the night and sleeping with you is one way to be close to you. There is nothing wrong with it. Give your child the security and reassurance she needs now, and she will be more confident. Deny her now, and it may cause more problems in the long run.
Go ahead and talk to her, see if she can articulate her feelings. She may not be able to. But it is ok to let her be close to you. She needs it. It will pass as she grows.