30 and pregnant

So my question is to the lady's over 30 that r pregnant or have been pregnant in there 30s. They other day I had my first ultrasound and everything looked great to me except the ultrasound technician told me on the way out that I have to make another appointment for 2 weeks (which I will be 14 weeks) to see if the baby is at risk for down syndrome. The thing I'm confused about is that never happened during my first pregnancy I probably got Maybe 4 ultrasound threw out my pregnancy and I find this weird (this is my 2nd pregnancy). So my question is lady's is this normal to basically have almost back to back ultrasounds? Or em I just overthinking it because she said down syndrome? I'm now just stressed and I see my OB this Thursday but idk I don't find this normal.