To add to what Wayne said, you will need more light or longer shutter speed to get that f stop up to f16. Longer shutter speed will require a tripod. Bright sun might get you there without a tripod. Use aperture priority and keep an eye on the shutter speed the camera selects. if necessary, drop the aperture down until your shutter speed comes up to a safe level for hand holding.
You could try your onboard flash [I feel Wayne cringing]. It will make some harsh shadows, but you will get a feel for using a higher f stop. So try this: onboard flash popped up... iso set to 100, manual exposure mode: 1/200 and f16. Auto focus should work ok for this. Use a single point. Focus at a mid distance point. If the whole flower does not come out sharp with this, back up a few inches.