How to explain birth control to mom

Started my birth control today and my mom is aware and is against it. She’s against it because she thinks it will damage my body badly. I’m taking it for my period because I throw up and am sexually active. She only thinks it’s for throwing up on my period. She goes ok after one month of taking it stop because then you’re good. Like? If it’s good for me I think I should continue taking it instead of only taking it for a month. She does NOT want me to continue.