Sis, normal yan! Every body shows differently, especially first time, a few of us moms in my circle showed quite big na by that point, some naman mas flat pa. At 19 weeks, maraming factors talaga, kung gaano kalaki ang baby, how much amniotic fluid, your body type, lahat yan. The best thing is to just ask your OB sa next checkup kung okay lahat, they'll make sure baby's growing right. Congrats on your first baby!