If you just don't have access to these people, or you flatly just don't want to, understood.
But, just as a bit of a thought experiment, if you don't already, what do you think would make you feel more inclined to talk openly and honestly to your parents or guardians about sex and sexuality? What would they need to do -- or not do -- in order for you to feel safe, and for those conversations to be useful and supportive for you?
That could be any number of things, for example, maybe it's that they would go get some more current information about sex and sexuality than they seem to have. Maybe they'd need to address any homophobia, biphobia or transphobia they have, or deal with sexism that colors their views. Perhaps they'd need to learn to be calmer, and more reactive, or to give you more room to have your own views and feelings instead of making theirs the only "right" ones or the only ones they're willing to listen to. Maybe you'd need them to do better at keeping confidences, or to be less judgmental. Those are just a few possibilities.
What do you think?
Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has. - Margaret Mead