What not to say to a perhaps future step sister?

that you dont want her around, that would be rude

It is probably best not to comment on your parents' romance, particularly their intimacy.

*Sigh* forgot the details once again: I'm meeting my dad's girlfriend and her daughter tomorrow. I'm 14 and so is she. She is Muslim and sometimes I can be racist so I know I'm going to avoid any racist jokes or anything. She is shy around her mother so she wants to spend time only with me. I don't know what I would talk about with her although I am excited to meet her and so is she. We are going to a bird sanctuary that I volunteer at and I am bad at telling people not to do something and I don't want to hurt her feelings if she does something against the rules. What should I ask her or bring up with her? Thank you.