I don't think she was:
- "My wife in practice if not yet by law"
- "I had hoped you would come to me last night" ... "I was tired"
- "Put your hands on me Jack" (sexually assertive)
- Asking him to draw her in the nude, having evidently few issues stripping off in front of him either (she does the kind of striptease with the sexy dressing gown!)
- She comments that he is trembling - he is the inexperienced one!
When he asks if she's nervous, and I don't quite remember when that is, I think it's pertaining to the fact that she's essentially leaving her family and whole life behind to join him, rather than being anything to do with sex.