Gender Scan 15+5

A

We had a private scan at 15+5 to find out the gender early

She was very confident our baby is a girl And I can definitely see why,

and no matter what angle she got her from there was nothing there, however we did not see the typical “3 lines” that everyone talks about.. should we be prepared that the 20 week scan might reveal a different gender or trust that we have seen for ourselves that there are no bits there ?