I want to test early but not too early. Help!

Ka

I ovulated this monday, but my period is predicted to be due on Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a>. I want to test early so I can create a cute way to tell our family if we are pregnant on Christmas day. What is a safe amount of early days to be able to test?