Your baby will start moving in the womb at 7 or eight weeks, however you won't be able to feel him kick until sometime between 16 and 22 weeks. Women who have been pregnant before are more likely to notice the first subtle kicks (called quickening) earlier than new moms because they have experience telling Baby's movements apart form other belly rumblings. Thinner women also tend to feel movement earlier than women who carry more weight.
At first Baby's movements will feel few and far between, and it will also be random as to when you feel them. There may be days when Baby is kicking up a storm and other days when you don't feel any movement. Despite the way it seems though, Baby is moving and kicking regularly. However, her jabs are not yet strong enough for you to feel. Later in the second trimester, Baby's movements will develop more of a regular pattern.
Fetal kicks have been described as feeling like gas, butterflies, popcorn popping, or a fish swimming around. You are m ore likely to feel early movements when you are having quiet time, and it will be easier to tell the first gentle taps apart from hunger pains of gas as you start to feel them more regularly.