Although this may appear daunting at first, it actually can be simplified to a few basics. The flower is nearly a perfect circle. The vase is made of narrow ellipses that are slightly skinnier at the top of the vase than they are at the bottom. The color scheme is nearly complementary; if you don't like it, change it to your preferred colors, or do a gray scale painting. The shape of the vase is plain. The background is uniform. There is only one rose to paint, and it is shaped like a shallow bowl facing the viewer. Practice getting that basic shape on some scrap paper, then tackle it for your finished flower. You won't need to add a lot of detailed petals if the basics are there to make it look like a flower.
Good luck! I look forward to seeing your artwork.