Sexually Active/Birth Control

My mother hates the fact that I'm growing up. But lately, my hormones have been uncontrollable. I just recently started dating this guy I've known for the longest time. He isn't a virgin, but I am. He regrets it. I talked to her before about birth control and she completely ignored me! I want to talk to her again but how do I approach this? I am 16. I'll be 17 in less than two months.