wish i can be friend with my parents

im studying in england at the moment, all of my friends all really good with their parent. they tell their parents everything about school life, relationship, friends, or sex...
i wish i can talk to my parents like my friend, i can't talk stuff to them like school, relationship, friends or sex because first, they not allow me a boyfriend until 16, second they never ask me about my school life, all the care is marks and exam. Is sex really a big deal? all my friend have sex and tell their parents and they doesn't care. But if i tell my parents, they will kill me.
Sometimes i really want to tell them everything about my happness or unhappness but they never know wats going on.