When should I say something

So I'm almost 10 weeks and my family doesn't know I'm pregnant. Me n my kids live with my granny and my s/o is living with us temporarily until he can find a job. I have my first ultrasound Monday, should I just wait until we get back on our feet to say something I don't want her to put him out bcuz I'm pregnant. And for those who wanna know I didn't get pregnant in her house lol. She has this thing about dreaming about fish and she woke up a few days ago saying well somebody pregnant. The last time she said she dreamt about it my God sister was pregnant,then before that it was me. I just don't want her or my family to be mad at me.