I wouldn't count on it at only 12 weeks. Bc most of the time they don't want to tell you for sure until your around 18 weeks. You can get a 3d-4d ultrasound done and find out at 16 weeks.
I'm 21 weeks and I found out yesterday I'm having a baby boy! :)
They thought I was 18 weeks but when they did my ultrasound they found out I was 24 weeks nd I'm having a boy:)
I'm scheduled to find out the sex of my baby at 19 weeks. I'm 18 weeks right now