Gender

So I'm 28 weeks and 5 days measuring a little ahead of that. Anyways I found out the gender at 20 weeks. And I'm so worried that it's wrong. I would still be happy and love my baby. I really don't care about the gender but I already got almost all my stuff. And I'm so stressed it's gonna be a boy. Anyone else got their ultrasound and didn't see the part they were saying???