Another ultrasound

I had my genetic counseling visit and ultrasound yesterday.  I am so amazed to see them moving around like they do!  At first, they weren't moving, but as she proceded to push on my belly with the u/s, I think she was bothering them! ha!  They started kicking and swinging their little arms....it is just so amazing!!!  At week 18 I go for another ultrasound (May 27th), and they should be able to tell me the sexes at that time.  I'm SO excited - can't wait to find out!!!!!  The heart rates are about 150bpm, and they measure a little over 6cm.  Looks like they are right on track so far.