How to talk to mom about having sex with boyf

I’m seventeen, and so is my boyfriend. We have been together for about seven/eight months now and I love him and he loves me. Our relationship moved very slowly at first-I didn’t even kiss him until we had been dating for two months-but now the pace has picked up and we are doing (safe) oral sex. I feel like I’m the next couple of months I will be ready to go all the way with him, because I love and trust him with my whole being. My mom always told me though, that if you’re not mature or ready enough to talk to a trusted adult about having sex with someone, then you shouldn’t be. So I need a way to openly bring up this conversation to her about me starting birth control and being ready for sex. My mom is really easy going and we have a great relationship. I’m looking for advice on how to bring up the topic and have a mature conversation with her Anything helps! Thanks!