[For the moment she's glad he can't see her face, and the mix of emotions that rise from the mention of that nickname. After a moment's pause, she writes, taking care with her words.]

I am glad to hear that.

You would have to decide that for yourself, I think. However, it does not offend me if that was a concern.

[And that's all she'll say on the matter, as she isn't quite brave enough to encourage nicknames, and she hardly wishes to discourage him either.]