How to get birth control

I'm 16, just lost my virginity and in a long term relationship that's as serious as a high school relationship can be. My boyfriend and I just started having sex and neither one of us want to make a mistake of having a child so young when our futures are so bright. We're both dedicated athletes and I'm a straight A student. I want to ask my parents for the birth control implant but I don't want them thinking I want it so that I can go sleep around with every guy in school. I'm also nervous because I've just started socializing and going to parties with friends and I've heard way to many stories about people either having drunk sex and getting pregnant or being raped or freak accidents happening and I want to be intimate with my boyfriend without having to worry about the possibility of having a kid. What's the best way to ask my parents to put me on birth control without telling them I'm sexually active? They know I've done oral and hand stuff and they basically let all of my siblings know what happened and they all make fun of me and mock me for it so telling my parents I've had sex is not an option.