She would have paid privately for NIPT screening. They email you the results if you get the blood test screening at 9/10 weeks plus. This is what she is referring to. If she had gender selection, she wouldn’t need to wait for email confirmation that it was a girl, she would know already as soon as she was pregnant as they only would have put XX fertilised eggs in.
I actually think she didn’t get gender selection now. Just from what she’s said about getting the reconstructive surgery because she thought she was done having kids, and this detail about the email revealing the sex. I don’t think she’s smart enough to lie this effectively.