It's perfectly reasonable and natural that the narrator should be concerned for her daughter's welfare. But she does come across as a mite over-protective, and that's where her fears start becoming unreasonable.
The mother doesn't want to let go of her child, which is perfectly understandable. But at some point she'll have to, like all mothers. What makes the mother's fear especially unreasonable is that she seems to be thinking about what's best for herself rather than what's best for her daughter.
She doesn't want her daughter to be a princess, because then she, her mother, wouldn't be able to sleep by her side. By the same token, she doesn't want her daughter to grow up to be a queen, because that would mean she wouldn't be able to go see her and rock her to sleep. It seems that the mother isn't prepared to let her daughter grow up. But then, she hasn't really grown up herself, such is the childish nature of her anxiety.