Not a parent. But, I have been in the situation of becoming accustomed to a step parent (i know that's not what you are but is similar.) I would say seems like you're doing all the right things. However, she is 12. About to be hitting those pivotal teen years. She may be a quiet person in general. I was quiet around each step parent more or less watching and understanding them. I think the fact you've had enjoyable and from the sounds of it non awkward interactions with her is key. Forced interactins are the worse. Make sure to give her enough space. In time she will open up to you. All your interactions with her have been good. My advice, be patient don't over worry yourself. This is a transition for her too.