ok.. So is it POSSIBLE for my b/g twins to switch sides

Vee
At 34 weeks? My boy has been on my right n girl on my left the whole time And this new ultrasound tech said the boy is on my left n girl right now.. I had an ultrasound 2 weeks ago wen i was 32 weeks and that u/s tech ddnt correct me wen i told her which was the boy n girl.