I get my first ultrasound done Monday what is something I can look for to see if it's a girl or boy

well now the dr thinks I'm farther along then the blood work showed he thinks I'm about 13 or 14 weeks

You really wont be able to tell. But if they show you legs try to see if you see something in between. Which is still definitely not definite. A baby at 11 weeks private areas are swollen so a little girls part could look like a boys it dies down at 15 weeks. I found out my boy at technically 10 because I had went to the ER after I got into a car wreck. & the lady checking my baby said she believes its a boy but since it might be swollen its not definite. I found out for sure at 16 weeks. She ended up being right