Had my first ultrasound

I saw my nurse practitioner and she did an ultrasound it took about a min for her to find where the sac was. And then she said I should be about 8 weeks but The baby is measuring 6w6d- 7w exactly. Going in 2 weeks to recheck. Do u see a yolk sac at all? What do you ladies think? I should be at least 7w4 days today. She also told me I have a tilted uterus! I've never been told that before and this is my 3rd baby.