How far along am I?

Matilda

I got my first ultrasound today but an intern was the one doing it so she told me she wouldn’t be able to tell me how far along I am and I would have to wait until my next appointment to find out. I was told that the black spot was the yolk sac, and I have heard before the placenta takes over at 8 weeks. But my mom said that by my ultrasound I look further than that. Can you still have a yolk sac and be over 8 weeks?