Help!!! 😭😳

Sooo, today I had my appointment for the Down syndrome and trisomy test and the technician also searched for the gender of my baby. I am currently 13 weeks and 5 days. She was able to see the baby's little part and she told us that it's definitely a babygirl. I'm really happy because that's what We wanted, a girl! However, I'm afraid that it might be to early to tell what the gender really is or that my baby is just not fully developed yet:/ I asked her what are the chances that it might change later on and she said "it won't your baby is for sure a baby girl!" She looked so sure but I'm wondering if maybe you guys had some opinions? Or anyone have similar stories and it was actually correct or baby's gender ended up changing? Thank you in advance! ☺️