I smoked marijuana a couple times and I'm 19 weeks pregnant will it show up in the baby when I have her?

Yes, it will show up in a meconium drug screen.

Yes, it will show up in a meconium drug screen.

What will they do about it?

It depends on your location. There is a new national initiative in the US that requires us to report to Child Protective Services if the baby is positive for drugs of any kind.