Advice please?????

I talked to my mom (I’m 16) about birth control. And I might be put on it. However I’ve been sexually active but she doesn’t know. And nor do I want her to know, i know it’s wrong, but she and my dad are very protective and strict. And she wants to go back with me when I go. Im okay with that but I would have her go out whenever it comes down to being checked. I know that the doctor will ask about being sexually active but how do I answer that? Do I say no and wait till my mom goes out to tell her that i am? I need help😓