Harmony testing

So I asked my OB about being able to tell the gender by blood test and she said it was illegal to just use the harmony test to tell baby's gender because of people having abortions due to gender selection. So I have to wait til I am 20 weeks to find out. I am bummed as I have seen so many women find out early. I kinda just wanted a jump start on my gender reveal to my friends and family cuz I wanna start stocking up on either pink or blue silly string.