Multiple factors are involved, and we'll discuss them.
- They're more likely to be in a stable relationship. So they can ask for what you want without fear of judgment, and they've got time to explore anything from role playing to BDSM. Plus, you might focus on preventing pregnancy (or trying to get pregnant) without the fear of STI transmission so that you might ditch condoms for the first time in exchange for other types of birth control.
- They're aware of how time is passing. Many people no longer feel young, mentally or physically, once they're in their thirties. Time is passing, and you can't get it back. So you try to make better use of time, and who has the time to be having bad or mediocre sex? This freedom allows women to speak up to get theirs when, previously, they may have just lay there and taken it.
- They recognize that everyone is self-conscious about their bodies. Other women. Their partners. So they take a deep breath and get into positions that might not be flattering but feel good. They have sex with the light on for the first time. They're sexually emboldened and having better sex because of it!
- They've had more partners and more time to masturbate. This allows women to better know what they like, which is vastly different from what men may like or even other women. The knowledge paired with a little timely impatience means women go for what they want.
- They've ditched culturally-imbued slut-shaming. Humans like sex, both men and women! But girls and women are often taught that it's bad to show this desire. Once a woman hits thirty, she might give up on denying herself that pleasure for another decade, and we think that's great!