"unless the weaker party confirms consent."

"So, from my past, my little lover, illegal as things were, smiled and asked me to continue. Is that consent?"

Yes. It was.
It ought to have been respected.

You ought to have got an opportunity to verify that yes, she wants you to continue... go back to bed.

I agree with asking extra questions from a child who´s young enough that it is otherwise unclear whether she understood what she was doing - but then she should have a realistic age-appropriate opportunity to say yes, and be respected.