mom keeps asking about my sex life.. :/

I'm 16 and i just got in my real first relationship i guess you could call it, and my mom likes a lot him and me and her have always had a really close relationship with each other but she keeps asking me about sex and stuff, I'm a virgin and she knows that but she keeps asking stuff like "have y'all talked about having sex?" "Is he a virgin?" "Has he asked you to have sex with him?" And what bothers me the most is she sat me down and told me that "when were ready to tell her and she'll get us protective or get me on birth control" and like great I'm glad she doesn't like forbid me to have sex or get mad at me and stuff, but when she ask that stuff it really disturbs me. like yes we've talked about sex were teenagers, no he's not a virgin, no he hasn't asked me to have sex with him but he told me that when I'm ready he'll make me feel comfortable and wont rush me. And when we are ready if ever, i doubt ill sit down and tell you before because i don't plan that stuff out, it happens when it happens and in the moment. of course i don't know when that will happen, but of course we'll use protection. I just don't know what to do or how to tell her i don't want her asking stuff like that, and its not that I'm uncomfortable, its just that to me that's personal stuff that i dont want to tell my mother.