I had my ultrasound but they can't tell the gender?

I get so jealous looking at these pregnant women knowing the gender of their baby when they aren't even 20 weeks yet! I get two that my insurance pays for, and at my 20 week appointment the tech said she thought it was a girl but wasn't sure. I was kind of frustrated because I need to start preparing and I can't do that without knowing the gender. I get my next ultrasound in 2 weeks (when I will be 6 months and one week pregnant) will they be able to tell then?