9 Weeks or 5 Weeks?

First meeting with the midwife went great.  She was nice, answered all my questions, and tolerated my borderline obsessive fear about tearing my hooohaa.  Her assistant took all my information about my last period, gynecological history, etc.  She came in and said, "It looks like you are 9 weeks along."  I whipped out the chart and she admitted that the chart would put me at 5 weeks along.  She said that correctly dating the pregnancy is very important, so they took blood to help date the pregnancy.  Based on the my HCG and progesterone levels, she's calling me tomorrow to schedule my next appointment, which will include an ultrasound that will hopefully show cashew's heartbeat.  She said it could be as early as next week or as late as three weeks from now.  Either way, that seems pretty soon to me.