Ultrasound confusion

So I know I was 18 weeks but not exactly sure how many days went for my anatomy scan brought my two-year-old along which what's in a good idea after we got there but it is what it is well my ultrasound tech was already in a mood she just done a triplet ultrasound and seemed to be in a rush which of course concerned me I've had four daughters and I know that you have to look for a 3 line indicator for it to be a female anywho as we're going along the ultrasound she says to me that she can't get clear measurements of a few things like the baby's spine for instancean indicated that I would probably have to come back for another ultrasound which is totally fine more pictures for me but when it came down to the sex of the baby she says to me that she thinks it's a girl don't take her a hundred percent sure but she thinks and still gave me a picture saying it's a girl yes I'm confused I just want to be sure before I start buying things either way I'm Happy Mama as long as baby is healthy