Mom problems

Not sure what to do about my mom... We started talking about birth control and sex and everything last night. I havnt been always close to her. I'm almost 16 and had sex once with my boyfriend of 2 years. She dosnt know. She keeps nagging me to tell her when I want to have sex so I can be on birth control. I used the condom and the pull out method (I will continue if I can). I asked her if I had sex would she tell my boyfriends family and she said yes. Like wtf! At least she was honest but why would you do that! It would ruin everything. I feel like she dosnt trust me. She has a reason... But I want my sex to be to myself. I don't think I'll have sex soon again because I'm busy. She also feels like if I have sex my boyfriend is gonna pressure me... My first time was amazing and it was my decision. I don't know why she won't give up and trust me. I feel smart enough but am I not. I'm happy! I'm in a serious relationship. She told me I should talk to other guys. My boyfriend and I talk too much aperantly . I'm happy ... Dose she not want me to be? :/