Before anything else, get checked up with a doctor, preferably an endochronologist. It is not normal to have no periods till 15. Tell your mother or aunty and do not shy or hasitate in telling this. You can allwas do safe sex using a condom but it is not good for your mental health to start your sex life so early. You should be ideally 18 or least 16.
well it is illegal at your age an if your boyfriend loves you he will wait for you 2 turn 16. but i dont think you can get pregnant but you should still have safe sex