Re: How to answer her when she asks how many women you've slept with?
You don't have lie. But who said you have to answer?
Just simply tell her you don't feel comfortable with that question. Or better yet, tell her it's too early to discuss such things.
It's not lying and she's not entitled to that information so you should feel no need to answer it. It's really and truly not her business.
P.S. I don't know if that's how 21 questions is played. But I have a better game than that. Won't catch you off guard.
"All things are subject to interpretation. Whichever interpretation prevails at a given time is a function of power and not truth."