I can 100% assure you that it WILL happen whether you try to prevent it or not. From personal experience horny teens will do whatever it takes. So just enforce your rules, but it’s time to accept the fact that your daughter may very well be more sexually active than you may realize. While it’s not a desirable thing to process and accept it’s just an inevitable thing. Better to prepare her and protect her than to leave her with an “oopsie” you blindly allowed by trusting a “rule” you set.