How do I change the shutter speed?
This is "shutter lag," the delay between pressing the shutter release button and the camera actually taking a picture. This is a common situation with many compact cameras. The camera has to focus on the subject, meter the exposure, and switch the circuitry from displaying on the screen to recording the image and saving it in memory. More sophisticated (and expensive) DSLRs eliminate this shutter lag by having more dedicated hardware for this.
With a compact camera, you can reduce the shutter lag by anticipating the shot. Press the shutter release button halfway to focus and meter the exposure. Continue to hold the shutter release button halfway until the right time, then press it the rest of the way.