Pregnancy?

So I am sure that I can’t have children because I have been having unprotected sex for the past 2 years and have never got pregnant but I’m 3 days late for my period however I never usually get my period on my predicted day any way but my boobs are really sore. How long should I wait before taking a test and is it possible I might actually be pregnant.

Just an update I’m 5 weeks pregnant 😀