how to..?

how should i tell my mom that i’m ready to have sex? my boyfriend and i have talked it over. we have been together for a few months but have been extremely close for a lot longer. we have always had that spark since we met. him and i have discussed it and we think it’s a good idea for us to talk to our parents about us having sex. especially because we want a safe and private place. he also wants me to talk to my mom about me getting on birth control and i’m completely ok with that. i would like to be as safe as possible, but i just don’t know how to talk to my mom. i’m only 15 but i think that i’m ready to take this step with him. i’m really close with my mom and just the other day she was talking to me about how i will always be her baby and i’m not allowed to grow up and this and that. idk i just think that i’m ready to make this step with this one person but i want it to be safe and i want it to be private. any tips?