K.J.
When I was about 20 weeks, I can remember that the movements were pretty sporadic. That being said, I am a HUGE advocate of counting kicks, especially later on in the pregnancy. My nearly lost my older son who was strangling in his umbilical cord at 36.5 weeks. I didn't feel movement for several hours and, thank God, I went to the hospital and they couldn't get him to move, so they did an emergency c-section.
Definitely ask your OB's office how much movement you should expect at this point. No sense in not asking.