NT Scan and Gender prediction

Julietta

So I just had my NT scan and the sonographer told me that she’s 70% sure that I have a girl. Bare in mind I’m only 12 weeks 6 days. I’m not sure how accurate this is and if any of you had this experience. I keep thinking it’s a NT scan so it’s much more sophisticated than a normal ultrasound so she must be right but I’ve heard some stories that it’s actually not accurate and male parts may grow later on . Any ideas?