I been with my GF for over a year and she has a recently 12 year old kid who acts like she is 8 years old or younger. I met the kid  around 5 months into the relationship. She also loves  being with her mom. She recently said to her mom that she doesn't like going to her dad and rather stay with her. Before me being introduced and a little after. The girl used to go to her dad's every other weekend but now it's been every two. She begs her mom not to send her to her dad's and my GF can't say no to her. I feel guilty that I don't have any feelings for this kid or that I find her annoying.