[There's really no happy answer to this, because she doesn't know what to say. In the end, she knows she would have to be blind not to realize that the things she says right now, could hurt or affect Zero.
The problem is, how does she feel about what happened? Does she regret it? Maybe a little. Her reasons why? It's not because it was Zero. The alcohol, maybe. There's guilt, too. But that isn't because it's Zero's fault either. Did it feel nice? Certainly. Does she want it to happen again...?
...
She bites her lip.]
I... I don't know how to respond.
[Glancing away, she decides to try and be as honest as possible. By this point that is what he deserves the most. No more lies or secrets. They've both agreed to that.]
It's not that I want to pretend it didn't happen. [Maybe a little bit, but her reasons will be explained.] It... It's just that I don't know how to respond to it yet. Everything is really new, so it- it's a little confusing for me.
[Drawing a breath, she struggles putting her thoughts into words, cheeks flushing darkly]
Everything felt- it felt good. So it was easy to get lost into that feeling. But at the same time I feel guilty for having felt that.