So going to see the mother in law tonight, The Hottest Computer Scientist in the Universe said that he thought his mom would guess before we tell her. We don't plan to tell anybody until after first trimester or first ultrasound, whichever is later. So that's a good two months away.
I think she won't guess, because we will be traveling for the last two weeks of the first trimester and too busy getting ready to leave to see her very often.
But I do think that whenever we tell her, she will say, "I knew it!" If we told her tonight that I was 13 wks pregnant (which I am not), she would come out with several reasons that had her allegedly "knowing" in advance: we are trying to buy a house, we are taking a trip, who knows what else. Hindsight being 20/20 she will posit all the "clues."
So just writing this now, and in a couple months I will have a reference to go back and see. :-P
P.S. For what it's worth, THCSITU thought I was giving myself away by "eating a lot." Guys, I eat. It's what I do. I'm pretty damn good at it.