4 months/ Baby bump or still jiggly πŸ˜•

Shantel β€’ Just found out I`m preggers with baby #2 😱
I am now 15w pregnant, and my stomach hasn't grown much. I'm a size 12 so it wasn't flat from the start. But my tummy is still about the same size it was at 8w. I see so many ladies at 4 months and they have a full baby bump. I know every woman's body is different but I'm scared my baby isn't developing accurately.