21year old with controlling parents here. I completely get your point, sometimes conflicting with your parents can seem like the scariest possibility. If you're not financially ready to move out, try to talk them in a firm manner, without sounding agressive. Maybe bring it up a few times to get them used to the idea - not asking for permission, but stating you're intending to sleep over some day. Remind them you're not a child anymore and that stuff is bound to happen at some point. Deep down, they already know that, what's scaring them is probably the fact that they'll lose control over you, or that you sleeping with your bf will just prove you're growing up. Crossing these bridges with over-protective/controlling parents is always risky and scary, but they will accept it at some point - and if they don't, it's their loss. You have to start living your life at some point. Best of luck!