A mama's love is like NO other. But like the ladies said above, I'd wait til you knew for sure :)
I doubt that your mom would kick you & her grand babies out , then again idk the situation . There really is no easy way to tell her but your gonna have to at some point, i'd just wait until you knew for sure so that you don't have any Unnecessary arguments . Good luck ! :)
I would wait until you know if you are or not and then tell her if you are. I meant will come out eventually and then you know where you stand and if you need to make new arrangements. Good luck and mom's are pretty understanding.