It's so normal to feel apprehensive, we were told our third was a girl, but I always worried they got it wrong and I'd have bought lots of pink stuff for nothing! It wasn't until she was out and DH said "It's definitely a girl" that I fully believed it LOL! It didn't help that a friend of ours had been told she was having a girl when in fact it was a boy...

But if it makes you feel any better, I have found out the gender with each of my children and they have been correct 100% of the time