step parenting

OK so I have been married for 3 years I have a 10 year old daughter but is away for the summer with my brother. My husband has 4 kids but his ex has custody they live in a different town, we see them every weekend and his 10 year old come and stays sometimes at our house. Well this past weekend my husband had to go to Mexico for a family emergency and yesterday his daughter called me crying she wanted to come to my house. I went to pick her up, my husband calls me and asked me if her mom let her come with me knowing he wasn't in town. she did, she just said oh your taking her I was like yeah if she wants to go she goes on OK let me get her clothes. I was surprised I'm not a bad step mother I care much for her because she is the only one that cares for my husband and wants to spend time with him and my other kids and me, but if I was her I would be like maybe when her dad comes back. what's your guys opinion