Help!

Rosalynn

So I really wanna start taking birth control and I brought it up to my mom a few times causally and she kind of just laughs at me and shakes her head. How do I convince her to take me to the doctors to go get it. I mean I'm growing up I'm almost 18 and leave for college in the next year or so. Things get crazy and happen quickly. Also I don't know where to start so that's why I need my mom.