This is weird I know...

Erin • Celebrated 5 years in November. Expecting our first Jelly Bean September 2016 ;)
This may seem a little weird but I need advice. This mommy is stressing! I live a little over 2 hours from all my family. I have been married for 5 years and this is our first child. My mom has been desperately wanting a grandbaby for a long time. She has told me in the past when I have a baby she wants it to be a big surprise and she wants me to tell her when I'm through my first trimester. I'm trying to do just that. Last night we had a rediculoous disagreement and she said to me, I'm going to let it go cause you have a secret pregnancy or something." I just said, " a secret pregnancy or something?" So now I feel like pretty much everything is ruined. I'm sure there's no way she actually knows. This isn't the first time she's said something about me being pregnant so nonchalantly. I planned on telling them for Easter. Does anyone have any ideas for how I can still really surprise her? I've been planning ways to tell her for years. I'm just going to be so upset if it's all ruined. Sorry for my rant!