Baby gender question. Help please 🙏🏼

Last week when I was 13 weeks and 2 days I went to the dr and checked everything was fine with the baby and I asked her for the gender and she told me 95% GIRL!! and am soooooo exited about it. But then when I told my family they told me it’s not possible to know that early. That sometimes the testicles are still inside and shows around 16 or 18 weeks. I don’t know if thats true or not but the dr seemed so sure! And now am confused it’s my 1st baby! And both ways am exited girl or boy as long as it’s healthy! But I want to know just to plan things and what to do and what to buy. So is what they say is true? And that I should wait? Or go with what the dr said? 🤔