How to tell

Okay ladies I know this may seem bad but I haven't told my mom that I'm pregnant with baby number 2 there reason behind it she can over step sometime and try to run everything , like when my sister had her girls she would call the hospital and bug the nurses about every little things. My mom lives in another state so it been easy to keep it from here and we haven't said anything on facebook yet. So I was going wait until we find out boy or girl to tell her since I'm 16 wk and should b find out soon but I'm husbands father kind let the cat out bag this morning on facebook so do I tell her now or do I just hope she doesn't see it?