Please help/ late period

So my period is currently 3 days late and I’ve never had a late period I’ve always had it come on time or before the day the app told me but I’m late and so I’m kinda scared because me and my bf had unprotected sex a couple of times about 2-3 weeks ago and my mom Doesn’t know I’m not a virgin but she knows that I’ve been wanting to ...anyways he didn’t cum inside of me any of the times we did it but... should I be worried ? Please help 🙏🏼