My cousin on my dads side has Down syndrome only because they were older and she had her birth…

My cousin on my dads side has Down syndrome only because they were older and she had her birth control in when she got pregnant... she had 2 other normal pregnancies when she was younger. Other than that I was tested with my son and I'm not a carrier for any other type of abnormality but I'm still nervous this time around for the harmony testing results for some reason?!