When/how should I tell him

So with my first pregnancy I told my dh right away but asked him not to tell anyone because I wanted to wait since I was only like 4-5 weeks. Today I got my bfp while he's at work and I'm debating about telling him now or waiting. The reason being is that I wanted to do something special to announce at Christmas for the whole family and don't want him to ruin the surprise with his excitement.