To tell or not to tell

I was not subtle on the subway trying to see if I could get a seat from anyone.  I stuck my belly right out there.  No seats.  Not surprised.  But there was my friend, Sarah, staring at my belly.  So she knows.  Which is kind of a relief b/c now I can talk about it with someone else. 

I was also not subtle in shul today sticking out my belly and holding my chumash at just the right spot so it highlighted my belly.  And another friend noticed, and then point blank asked me.  That was actually kinda funny.  "Are you expecting a baby?"  I said "I Hope so!"

So now two people know.  And according to the first one, people are speculating.  Oy.  So do I tell my family?  or just surprise them?  I really like the idea of just showing up with my big belly and surprising people.  And they're going to notice eventually.  But if I don't tell them, and just show up at the bar mitzvah in a month with a giant belly, I can imagine them being really angry, and I don't want that.  And how long before someone notices and figures it out and tells them before I do?  Can you imagine?! 

What do I dooooo?!