Looks like the top of the nearest stamen is the sharpest part and you may have focussed on that.
Tripod - you could lower your shutter speed a lot to permit a smaller aperture and get more of the shot sharp.
If an indoor shot then wind was no problem. If outdoors and the plant was blowing about maybe the focussing could not keep up - use a wind break.
Turn off auto focus and focus manually, Jenny.
Experiment with taking shots with the camera focussed on various parts of the flower to see what result pleases your eye the most.