You will be feeling the baby move and kick. Get the book titled "What to Expect When You Are Expecting" and it covers each week. It will give you answers on what changes at each time period and with each week that passes how things will be changing so that you know what to expect.
Around 21 weeks you will begin to feel the baby move. It can be sooner or later but will begin around that time. You actually should feel relatively good at this point in your pregnancy as you are past the morning sickness - first trimester issues and haven't gotten to the uncomfortable part of the third trimester.
For first time mothers, 21 weeks is about the time when they will begin to feel the baby move. However, some may feel movement earlier, and some later. Also, if you haven't yet had a growth ultrasound, you will soon.
You should be feeling the baby move by now. If it your first, it may still feel like gas or tiny muscle spasms, but you should feel something. Some people experience false labor already by this point. Also, you might start feeling some back pain as the baby is growing bigger.
During your 21st week of pregnancy you will start to feel more movement from the baby. In addition you will develop a more defined baby bump and have to start wearing more maternity clothes. Your baby is growing very fast right now, and is going through many changes in the process.