5 days late!

So I'm sexually active, and I've been getting some pain during sex when I ride. It was worse but we didn't do it for a couple days and it felt a lot better. But I'm 5 days late for my period. My boyfriend thinks I'm pregnant and he's scared. We're only 15 and 16 (any comments about our ages will be deleted immediately), and I've haven't even had my period for a full year. I still have months where I'm really late and really early. Also, my cervix is high and Open. So what do you guys think? I need some other opinions !!!!