It's not very ladylike, but hell if ladylike is a requirement. It doesn't seem like the sort of thing that makes a lady overly happy to have to be all the time, and a happy Sophie is much better than an overly dignified but unhappy Sophie.

But the idea that he'll come up a tree?

That's neither ladylike nor fun and happy. That's just ridiculous. He's got nothing to say to it except to arch a brow up at her.