Ok. Was not expecting that.
I joking reply with the standard, "Thirty-five."
She's not having that. She replies, "No. Not a good answer. You can't say thirty-five. Because whatever age you say, like thirty five, I will get to that age and then you will just add five years. So it's more like whatever age+5=dating age for infinity"
I don't really see an issue with this particular equation, but I know this woman-child sitting next to me and I can sense that she is genuinely searching for an answer and she is not in the mood for further joking.
I asked her if there is someone she is interested in dating right now. (and hold my breath)
She tells me that there is not. ( I breathe again)
I think quietly for a moment and tell her that when she does come across someone that she likes in that way, maybe we could talk about dating then and what "dating" might mean for that age and what sort of expectations a partner might have and what our expectations/limitations might be. This satisfied her.