How can I convince my mom to let me on birth control?

Katie
My parents are very anti-birth control. They grew up in the age where birth control was pretty sketchy so they aren't big fans. I tried to tell my mom that my period hurt me and my cramps were bad and she suggested essential oils for me instead... Same with acne.
Now that I'm going off to college, I'm probably going to need it for another reason. My parents are very strict and also very judgmental of younger kids having sex so I have never really brought that angle up. 
Every time I bring up birth control with her she just shuts it down... I want to be safe in college and I also want less painful periods. Please help!