So, its really a girl, right?

Hi everyone,
I'm having my first baby. We went in for the "big reveal" at 18+5. It was a 3D ultrasound. The baby looked great, all its little baby parts in order and they told us it was a girl!
We were very excited, but a bit confused. We both thought we were actually looking at a picture of a boy. I've been studying the three-white lines of confirmed girl ultrasounds, but this looks a bit different. The line in the middle (with the arrow) seems to be, eh, protruding! It also looks like it might be two lines? Or am I looking at the wrong thing? Are the two thick white lines on the side her legs or her labia? Or neither because she's actually a he!
Is it the center bit that I should be focusing on?
Basically I have no clue what Im looking at. If someone could tell me if its a girl and explain what I'm actually looking at I'd be very grateful!
Thanks!
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PS - Here's a second pic the tech said connoted gender. She said that flat line said girl - but she didn't say what it actually was.
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I can't figure out what the second pic is but the first one looks very girly to me x

Girl for sure! First image is showing labial folds. 2nd image is a side view of clitoris. Congrats :)