Birth control

Valerie

So in 3 months I’m going to be 16 , me and my boyfriend have had protected sex about a few times , and my mom told me to tell her when I knew I wanted to be on birth control . I want to ask her but I just don’t want to bring up when and where I’m having sex conversation even though she’s just my mom and wants to make sure I’m safe . How should I ask about birth control ?!