I am 18 1/2 w and still haven't felt the baby move. From what I understand that is normal, but it is very unsettling for me. I heard the HB at my doctor's appt. last Friday and that is always great to hear. I am not due for the big u/s for another couple of weeks. Again, I know not to feel at this stage is probably normal, but it just makes me worry. I am sure this is more stressful since it is my 1st pregnancy. And I think I am just super emotional now which doesn't help.
Re: when are you supposed to feel the baby move?
Raeleigh Elizabeth http://theturnerpage.blogspot.com/
It will prob happen in the next few weeks
. They say most first time moms don't feel flutters until around 22 weeks or so. Your baby's positioning can really affect how/when you feel him/her. But don't worry.. it'll happen hun 
I felt flutters at 19w1d, and my first lil kicks at 20w3d.
http://balletandbabies.blogspot.com
I felt LO for sure the first time at exactly 18 weeks. Looking back I know there were earlier movements, but I wasn't sure it was baby then.
That being said, I've read that, on average, first time mothers feel baby during week 19. So you'll probably be feeling baby soon!