Stepmom question?

What are the responsabilities of a stepmom? I'm hoping to meet my step daugther soon, I also have a daughter with my husband, what if she doesnt like me? I'm a nice person, and I want her to be with her dad who she hasn't seen over two years and I also want her to meet her sister. She is 8 years old, and my daughter is 2, I met her when she was 3 but havent seen her since. Thanx.