Gaining

How can you tell when your belly is finally going to stop ballooing out straight and just roll over instead? What are the signs it's about to happen? I'm starting to get a line on the sides of my belly. Is that where I will roll over when I'm bigger?

Yes that is the line. When you lean to the side you will see it more as you get bigger you the amount you will need to lean will decrease, until you wont have to lean at all.

Yay, I can't wait

Two types of fat, visceral and subcutaneous.

Visceral is hard and behind your abs making belly stick out, subcutaneous is over abs and everywhere else. Eating gains visceral faster, cardio burns visceral faster.

Exercise or just wait out your daily metabolism over a year if you want flab over the pregnant look.