Scans

The place I go to for my scans only does abdominal scans, I went for one at 5 weeks and nothing could be seen, then I went for one at 6 weeks and the gestational sac was visible, I Am due to go back on Thursday at 7 weeks I’m hoping to see the yolk sac and fetal pole, is it normal to see everything later on an abdominal scan as I know vaginal scans show baby a lot earlier.