The first "pop"

I've heard from several friends that there's a point where your baby belly just "pops" and you can finally tell that the mom-to-be isn't just getting chubby but there's a baby growing inside. This has recently happened, in a small way, but its a start.  It occurred last Sunday to be exact.  I'm 5 months along now and until very recently most of my Mexican friends would look at me with this "you've got to be kidding" look--like I was joking about being pregnant.  Well, now there's a little proof.