I would talk about things like where she grew up, what is the weather like, what are her favorite colors, seasons, foods etc. What are some of her hobbies? What was her best subject in school, her favorite sports etc. I think you get the picture.
I would say the main thing is to get the point across that you ARE GENUINELY interested in her (and not just the baby).
Also, if you are nervous, let her know.I guarantee she feels the same way!
It would be good to laugh about to let out some of the anxiety. If this baby is meant to be yours, it will be. Please keep the faith!