I'm 2 days late for my period...?

I'm 16 years old, and I know at this age periods can be irregular. But for the past year and a half my periods have always been on time. I mean, I can pinpoint when it will start during the day. Now I'm 2 days late so I'm scared. I haven't been under any stress, no new medicine, nothing has changed. Me and my boyfriend have been having for about 6 months now. We are always careful. We have, in the heat of the moment, had without a condom. But he always pulled out. One of these times was about 2-3 weeks ago. It was the last time we had and we just got caught up. My mom always told me if I was having to just tell her and she would put me on birth control, but I'm too scared to tell her because I'm scared she'll be mad. But anyway, I'm sorry for telling you like my whole lfie store I'm just scared and nervous. Nothing feels different except that I'm 2 days late. Like I guess I just want some advice on what to do... I don't know how to tell my boyfriend that I'm late without scaring him but I just want to talk to someone about it to maybe make me feel better. And I'm sorta a tomboy so I literally have no girl friends. :/