First Scan Booking

I booked in for my first scan on Thursday - scan date: Monday February 11th, 2013.
That will be my 10 week period. I am unsure as to why my doctor has scheduled me to have a scan then as I thought that the first one was always at 12 weeks. The doctor I am seeing currently is about to leave and will leave the clinic in my 10 week period so maybe she wants to check up on me before I leave although it means I will be required to get another scan 2 weeks after possibly at my 12 weeks? It will be a cost at my pocket to get 2 scans so quickly so I'm unsure what I should do.