When do they sit?

At what point does the baby stop laying like straight across the tummy? Earlier today I know for a fact she was because she was hiccuping and every time she did, I’d feel her kick my on one end and on the other I’d feel her head lol. But I know she lays like that most of the time because when she does my stomach is less stuck out, it gets wider when I look down at it and then when she sits up, it sticks out more.