how should i say it

So my mom and I have a really good relationship. I could tell her anything, she trusts, loves me, and gives good advice. The one advice I would never forget is " If you are not ready for a kid, then your not ready for sex." That advice has been stuck for my head for a really long time. Now that I'm about to turn 18 in 6 months, I feel I'm ready to have sex but with birth control obvio. But idk how to tell her that I'm ready to have sex and I want to be in birth control?